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HK1205280A1 - Exposure apparatus, exposure method, and device manufacturing method - Google Patents

Exposure apparatus, exposure method, and device manufacturing method Download PDF

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Publication number
HK1205280A1
HK1205280A1 HK15105600.4A HK15105600A HK1205280A1 HK 1205280 A1 HK1205280 A1 HK 1205280A1 HK 15105600 A HK15105600 A HK 15105600A HK 1205280 A1 HK1205280 A1 HK 1205280A1
Authority
HK
Hong Kong
Prior art keywords
heads
stage
head
exposure
region
Prior art date
Application number
HK15105600.4A
Other languages
Chinese (zh)
Other versions
HK1205280B (en
Inventor
柴崎祐
柴崎佑一
Original Assignee
株式会社尼康
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 株式会社尼康 filed Critical 株式会社尼康
Publication of HK1205280A1 publication Critical patent/HK1205280A1/en
Publication of HK1205280B publication Critical patent/HK1205280B/en

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Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/70—Microphotolithographic exposure; Apparatus therefor
    • G03F7/70058—Mask illumination systems
    • G03F7/70091—Illumination settings, i.e. intensity distribution in the pupil plane or angular distribution in the field plane; On-axis or off-axis settings, e.g. annular, dipole or quadrupole settings; Partial coherence control, i.e. sigma or numerical aperture [NA]
    • G03F7/70108—Off-axis setting using a light-guiding element, e.g. diffractive optical elements [DOEs] or light guides
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/20—Exposure; Apparatus therefor
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/70—Microphotolithographic exposure; Apparatus therefor
    • G03F7/70058—Mask illumination systems
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/70—Microphotolithographic exposure; Apparatus therefor
    • G03F7/70058—Mask illumination systems
    • G03F7/70191—Optical correction elements, filters or phase plates for controlling intensity, wavelength, polarisation, phase or the like
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/70—Microphotolithographic exposure; Apparatus therefor
    • G03F7/70483—Information management; Active and passive control; Testing; Wafer monitoring, e.g. pattern monitoring
    • G03F7/70491—Information management, e.g. software; Active and passive control, e.g. details of controlling exposure processes or exposure tool monitoring processes
    • G03F7/70516—Calibration of components of the microlithographic apparatus, e.g. light sources, addressable masks or detectors
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/70—Microphotolithographic exposure; Apparatus therefor
    • G03F7/70691—Handling of masks or workpieces
    • G03F7/70716—Stages
    • G03F7/70725—Stages control
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/70—Microphotolithographic exposure; Apparatus therefor
    • G03F7/70691—Handling of masks or workpieces
    • G03F7/70758—Drive means, e.g. actuators, motors for long- or short-stroke modules or fine or coarse driving
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/70—Microphotolithographic exposure; Apparatus therefor
    • G03F7/70691—Handling of masks or workpieces
    • G03F7/70775—Position control, e.g. interferometers or encoders for determining the stage position
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/70—Microphotolithographic exposure; Apparatus therefor
    • G03F7/708—Construction of apparatus, e.g. environment aspects, hygiene aspects or materials
    • G03F7/70975—Assembly, maintenance, transport or storage of apparatus
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F9/00—Registration or positioning of originals, masks, frames, photographic sheets or textured or patterned surfaces, e.g. automatically
    • G03F9/70—Registration or positioning of originals, masks, frames, photographic sheets or textured or patterned surfaces, e.g. automatically for microlithography
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F9/00—Registration or positioning of originals, masks, frames, photographic sheets or textured or patterned surfaces, e.g. automatically
    • G03F9/70—Registration or positioning of originals, masks, frames, photographic sheets or textured or patterned surfaces, e.g. automatically for microlithography
    • G03F9/7003—Alignment type or strategy, e.g. leveling, global alignment
    • G03F9/7046—Strategy, e.g. mark, sensor or wavelength selection
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/027—Making masks on semiconductor bodies for further photolithographic processing not provided for in group H01L21/18 or H01L21/34
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49002—Electrical device making
    • Y10T29/49004—Electrical device making including measuring or testing of device or component part

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Health & Medical Sciences (AREA)
  • Environmental & Geological Engineering (AREA)
  • Epidemiology (AREA)
  • Public Health (AREA)
  • Manufacturing & Machinery (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Exposure And Positioning Against Photoresist Photosensitive Materials (AREA)
  • Container, Conveyance, Adherence, Positioning, Of Wafer (AREA)
  • Exposure Of Semiconductors, Excluding Electron Or Ion Beam Exposure (AREA)
  • Length Measuring Devices By Optical Means (AREA)
  • Optical Transform (AREA)

Abstract

An exposure apparatus in equipped with an encoder system which measures positional information of a wafer stage (WST1) by irradiating a measurement beam using four heads (60 1 to 60 4 ) installed on the wafer stage (WST1) on a scale plate (21) which covers the movement range of the wafer stage (WST1) except for the area right under a projection optical system (PL). Placement distances (A, B) of the heads (60 1 to 60 4 ) here are each set to be larger than width (a i , b i ) of the opening of the scale plates (21), respectively. This allows the positional information of the wafer stage to be measured, by switching and using the three heads facing the scale plate out of the four heads according to the position of the wafer stage.

Description

Exposure apparatus, exposure method, and device manufacturing method
The present application is a divisional application of an invention patent application having an application number of 201080037585.4, an application date of 24/8/2010, and an invention name of "exposure apparatus, exposure method, and device manufacturing method".
Technical Field
The present invention relates to an exposure apparatus, an exposure method, and a device manufacturing method, and more particularly, to an exposure apparatus and an exposure method used in a photolithography process for manufacturing a microdevice (electronic device) such as a semiconductor device, and a device manufacturing method using the exposure method.
Background
Conventionally, in a photolithography process for manufacturing electronic devices (micro devices) such as semiconductor devices (e.g., integrated circuits) and liquid crystal display devices, a step and repeat (step and repeat) type projection exposure apparatus (so-called stepper) or a step and scan (step and scan) type projection exposure apparatus (so-called scanning stepper (also called scanner)) is mainly used.
Such an exposure apparatus has been increasingly required to have high overlay accuracy (alignment accuracy) in accordance with the miniaturization of device patterns for high integration of semiconductor devices. Therefore, the demand for higher accuracy in position measurement of a substrate such as a wafer or a glass plate on which a pattern is formed is increased.
As a device responding to such a request, for example, patent document 1 discloses an exposure device including a position measurement system using a plurality of encoder type sensors (encoder heads) mounted on a substrate stage. In this exposure apparatus, the encoder head irradiates a measuring beam on a scale arranged to face the substrate stage, and receives a return beam from the scale to measure the position of the substrate stage.
However, in an exposure apparatus including the position measurement system described in patent document 1, in actual operation, an encoder head facing a scale is switched and used from among a plurality of encoder heads according to the position of a substrate table. Furthermore, when the encoder head to be used is switched, continuity of the measurement result of the substrate stage position must be ensured.
Prior art documents
[ patent document 1] specification of U.S. patent application publication No. 2006/0227309
Disclosure of Invention
The present invention has been made in view of the above circumstances, and according to an aspect 1, there is provided an exposure apparatus 1 for sequentially exposing a plurality of divisional areas arranged in a matrix on an object with an energy beam and forming a pattern on each of the plurality of divisional areas, the apparatus comprising: a movable body that holds an object and moves along a predetermined plane; a position measurement system including a plurality of heads provided on the movable body, the position measurement system determining position information of the movable body based on measurement results of a predetermined number of heads that irradiate a measurement beam on a measurement surface, which is arranged to face the movable body so as to be substantially parallel to the predetermined plane and has an opening in a part thereof, and receive a return beam from the measurement surface, to measure a position of the movable body in each measurement direction; and a control system for driving the movable body based on the position information obtained by the position measuring system and switching at least one of the predetermined number of heads for calculating the position information of the movable body to another head depending on the position of the movable body; among the plurality of heads, a separation distance between two heads separated in the 1 st direction in the predetermined plane is larger than a width of the opening in the 1 st direction.
According to this apparatus, the encoder head facing the scale can be switched to use from among the plurality of encoder heads depending on the position of the moving body, so that the position information of the moving body can be measured.
According to the 2 nd aspect of the present invention, there is provided a 2 nd exposure apparatus for sequentially exposing a plurality of divisional areas arranged on an object with an energy beam and forming a pattern on each of the plurality of divisional areas: the device includes: a moving body that holds an object to move along a predetermined plane; a position measurement system including a plurality of heads provided on the movable body, and determining position information of the movable body based on measurement results of a predetermined number of heads among the plurality of heads, the predetermined number of heads irradiating measurement beams onto a measurement surface which is arranged opposite to the movable body and is substantially parallel to the predetermined plane and which measures a part of the ineffective measurement region and receiving return beams from the measurement surface to measure positions of the movable body in each measurement direction; and a control system for driving the movable body while switching a head for calculating position information of the movable body, based on the position information obtained by the position measurement system; the separation distance between two heads in the 1 st direction in the predetermined plane among the plurality of heads is determined in consideration of the size of the measurement ineffective area in the predetermined direction.
According to this apparatus, since the separation distance between the two heads is appropriately determined in consideration of the size of the measurement ineffective area in the predetermined direction, the positional information of the movable body can be measured without switching the heads while the movable body is moved in the predetermined direction at a constant speed in order to form a pattern in the divided area on the object, which is formed as a result of the pattern formation. Therefore, the pattern can be formed on the object with good accuracy.
According to the 3 rd aspect of the present invention, there is provided a 3 rd exposure apparatus for sequentially exposing a plurality of divisional areas arranged in a matrix on an object with an energy beam to form a pattern in each of the plurality of divisional areas, the apparatus comprising: a moving body that holds an object to move along a predetermined plane; a position measurement system having a plurality of heads provided on the movable body, and determining position information of the movable body based on measurement results of a predetermined number of heads among the plurality of heads, the predetermined number of heads irradiating measurement beams onto a measurement surface which is arranged to face the movable body, is substantially parallel to the predetermined plane, and has an opening in a part thereof, and receiving return beams from the measurement surface to measure positions of the movable body in respective measurement directions; and a control system for driving the movable body based on the position information obtained by the position measuring system, and switching at least one of the predetermined number of heads for calculating the position information of the movable body to another head depending on the position of the movable body; in a first region where a first head group among the plurality of heads and a second head group where at least one head is different from the first head group, the first head group and the second head group include heads that face the measurement surface, position information of the movable body is obtained from a measurement result of the first head group, and after the movable body is moved at a constant speed in a 1 st direction of the predetermined plane in order to form the pattern on a land region that is caused to be formed among the plurality of land regions, the head for calculating the position information of the movable body is switched to the second head group before only the head included in the second head group moves from the first region to the second region that faces the measurement surface.
According to this apparatus, while the movable body is moved at a constant speed in the 1 st direction in order to form a pattern in the divided region of the object, which is subject to formation, the position information of the movable body can be measured without switching the head. Therefore, the pattern can be formed on the object with good accuracy.
According to the 4 th aspect of the present invention, there is provided a 1 st exposure method for sequentially exposing a plurality of divisional areas arranged in a matrix on an object with an energy beam to form a pattern in each of the plurality of divisional areas, the method comprising: an operation of obtaining position information of a movable body that holds the object moving along a predetermined plane, based on measurement results of a predetermined number of heads of a plurality of heads provided on the movable body, the predetermined number of heads irradiating measurement beams onto a measurement surface that is arranged opposite to the movable body and is substantially parallel to the predetermined plane and receiving return beams from the measurement surface to measure positions of the movable body in respective measurement directions; an operation of moving the movable body at a constant speed in the 1 st direction within the predetermined plane in order to form the pattern in a formed one of the plurality of divisional areas based on the position information; and switching at least one of the predetermined number of heads for calculating the position information of the moving body to the other head depending on the position of the moving body after the moving body moves at the constant velocity.
According to this method, during the movement of the movable body in the 1 st direction at a constant velocity for the purpose of forming a pattern on the region of the object subjected to the formation, the positional information of the movable body can be measured without switching the head. Therefore, the pattern can be formed on the object with good accuracy.
According to the 5 th aspect of the present invention, there is provided a 2 nd exposure method for sequentially exposing a plurality of divisional areas arranged in a matrix on an object with an energy beam to form a pattern in each of the plurality of divisional areas, the method comprising: an operation of obtaining position information of a movable body that holds the object moving along a predetermined plane, based on measurement results of a predetermined number of heads of a plurality of heads provided on the movable body, the predetermined number of heads irradiating measurement beams onto a measurement surface that is arranged opposite to the movable body and is substantially parallel to the predetermined plane and receiving return beams from the measurement surface to measure positions of the movable body in respective measurement directions; an operation of driving the movable body stepwise toward a constant velocity movement start point for forming the pattern for the divisional area that is formed out of the plurality of divisional areas, based on the obtained position information; and switching at least one of the predetermined number of heads for calculating the position information of the moving body to the operation of the other head depending on the position of the moving body before the moving body is moved at the same speed in the 1 st direction on the predetermined plane in order to form the pattern in the divided region due to the formation after the step driving.
According to this method, during the moving body is moved at an equal speed in the 1 st direction in order to form a pattern on the region of the object subjected to the formation, the positional information of the moving body can be measured without switching the head. Therefore, the pattern can be formed on the object with good accuracy.
According to the 6 th aspect of the present invention, there is provided a 3 rd exposure method for sequentially exposing a plurality of divisional areas arranged in a matrix on an object with an energy beam to form a pattern in each of the plurality of divisional areas, the method comprising: an operation of obtaining position information of the movable body from a measurement result of a 1 st head group in a 1 st region where a head included in the 1 st head group and a 2 nd head group, at least one head being different from the 1 st head group, among a plurality of heads provided on the movable body that holds the object to move along a predetermined plane, oppose a measurement surface provided substantially parallel to the predetermined plane, and moving the movable body at a constant speed in a 1 st direction in the predetermined plane in order to form the pattern in a divisional region that is formed among the plurality of divisional regions, based on the position information; and switching the head for calculating the position information to the operation of the 2 nd head group before the moving body moves from the 1 st region to the 2 nd region where only the heads included in the 2 nd head group face the measurement surface after moving at the constant speed.
According to this method, during the constant-speed movement of the movable body in the 1 st direction for the purpose of forming a pattern on the object in the region subjected to formation, the positional information of the movable body can be measured without switching the head. Therefore, the pattern can be formed on the object with good accuracy.
According to the 7 th aspect of the present invention, there is provided a 4 th exposure method for sequentially exposing a plurality of divisional areas arranged in a matrix on an object with an energy beam to form a pattern in each of the plurality of divisional areas, the method comprising: an operation of obtaining, from the measurement result of the 1 st head group, position information of the movable body in which the object moves along a predetermined plane in a 1 st region of the plurality of heads provided on the movable body, wherein the 1 st head group and a head included in a 2 nd head group in which at least one head is different from the 1 st head group are opposed to each other on a measurement plane provided substantially parallel to the predetermined plane, and the operation of driving the movable body in steps toward a constant-speed movement start point for forming a pattern for a division region which is formed among the plurality of division regions based on the position information; and after the step driving, switching the head used for measuring the position information to the 2 nd head group before the moving body moves from the 1 st region to only the 2 nd region where the head included in the 2 nd head group faces the measurement surface in order to form the pattern in the divided region caused by the formation from the starting point in the predetermined plane to move at the equal speed in the 1 st direction.
According to this method, while the movable body is moved at a constant speed in the 1 st direction in order to form a pattern in the divided region of the object, which is subject to formation, the position information of the movable body can be measured without switching the heads. Therefore, the pattern can be formed on the object with good accuracy.
According to the 8 th aspect of the present invention, there is provided a 4 th exposure apparatus for sequentially exposing a plurality of divisional areas arranged in a matrix on an object with an energy beam to form a pattern in each of the plurality of divisional areas, the apparatus comprising: a moving body that holds an object to move along a predetermined plane; a position measurement system having a plurality of heads provided on the movable body, and obtaining position information of the movable body based on measurement results of a predetermined number of heads among the plurality of heads, which irradiate a measurement beam onto a measurement surface arranged to be substantially parallel to the predetermined plane in opposition to the movable body, receive a return beam from the measurement surface, and measure a position of the movable body in each measurement direction; and a control system that drives the movable body based on the position information obtained by the position measurement system, and switches at least one of the predetermined number of heads for calculating the position information of the movable body to another head when the movable body moves at a constant speed in a direction other than the 1 st direction within the predetermined plane in order to form the pattern in the divisional area that is formed among the plurality of divisional areas.
According to this apparatus, the head is not switched while the movable body is moved in the 1 st direction at a constant speed to form a pattern in the divided region of the object. Therefore, the pattern can be formed on the object with good accuracy.
According to a 9 th aspect of the present invention, there is provided a 5 th exposure method for sequentially exposing a plurality of divisional areas arranged in a matrix on an object with an energy beam to form a pattern in each of the plurality of divisional areas, the apparatus comprising: an operation of obtaining position information of the movable body moving along a predetermined plane from measurement results of a predetermined number of heads among a plurality of heads provided on the movable body, the predetermined number of heads irradiating measurement beams onto a measurement surface which is arranged opposite to the movable body, is substantially parallel to the predetermined plane, has an opening in a part thereof, and receives return beams from the measurement surface to measure positions of the movable body in respective measurement directions; and switching at least one of the predetermined number of heads for calculating the moving body position information to the other heads depending on the position of the moving body when the moving body moves at a constant speed in a direction other than the 1 st direction in the predetermined plane in order to form the pattern in the divided region due to the formation.
According to this method, the head is not switched while the movable body is moved at a constant speed in the 1 st direction in order to form a pattern in the region of the object subjected to formation. Therefore, the pattern can be formed on the object with good accuracy.
According to a 10 th aspect of the present invention, there is provided a component manufacturing method comprising: an operation of forming a pattern on an object by using any one of the 1 st to 5 th exposure methods of the present invention; and developing the object on which the pattern is formed.
Drawings
Fig. 1 is a view schematically showing the configuration of an exposure apparatus according to an embodiment.
Fig. 2 is a diagram showing a configuration of an encoder system disposed around a projection optical system.
Fig. 3 is a diagram showing a configuration of an encoder system disposed around an alignment system.
Fig. 4 is an enlarged view of a portion of the wafer stage, cut away.
Fig. 5 is a diagram showing the arrangement of encoder heads on the wafer stage.
Fig. 6 is a block diagram showing a main configuration of a control system related to stage control in the exposure apparatus of fig. 1.
Fig. 7 is a diagram (1 thereof) showing the relationship between the arrangement of the encoder head and the scale plate and the measurement region of the encoder system.
FIG. 8 is a view showing the wafer W of FIG. 7 in an enlarged scale1The figure (a).
Fig. 9 is a diagram (1) showing a movement locus of an exposure center on a wafer in exposure by the step-and-scan method.
Fig. 10 a is a diagram (1) showing an example of an encoder head switching program, fig. 10B is a diagram showing a temporal change in the drive speed of the wafer stage before and after the encoder head switching, and fig. 10C and 10D are diagrams (2 and 3) showing an example of an encoder head switching program.
Fig. 11(a) and 11(B) are diagrams for explaining the continuation calculation and the continuation processing.
Fig. 12 is a diagram showing an overview of the connection processing at the time of switching the heads of the encoder.
Fig. 13 is a diagram (2) showing the relationship between the arrangement of the encoder head and the scale plate and the measurement region of the encoder system.
FIG. 14 is a view showing the wafer W of FIG. 13 in an enlarged scale2The figure (a).
Fig. 15 is a diagram (2) showing a movement locus of an exposure center on a wafer in exposure by the step-and-scan method.
Fig. 16 a to 16C show an example of an encoder head switching routine (fig. 4 to 6).
Fig. 17(a) and 17(B) are diagrams for explaining the principle of the encoder system measurement error generated with the acceleration of the wafer stage.
Detailed Description
An embodiment of the present invention will be described below with reference to fig. 1 to 17 (B).
Fig. 1 shows a schematic configuration of an exposure apparatus 100 according to an embodiment. The exposure apparatus 100 is a projection exposure apparatus of a step-and-scan type, that is, a so-called scanner. As will be described later, in the present embodiment, the projection optical system PL is provided, and hereinafter, the direction parallel to the optical axis AX of the projection optical system PL is defined as the Z-axis direction, the direction in which the reticle and the wafer are relatively scanned in a plane orthogonal thereto is defined as the Y-axis direction, the direction orthogonal to the Z-axis and the Y-axis is defined as the X-axis direction, and the rotational (tilt) directions about the X-axis, the Y-axis, and the Z-axis are defined as the θ X, the θ Y, and the θ Z directions, respectively.
Exposure apparatus 100 includes illumination system 10, reticle stage RST for holding reticle R, projection unit PU, wafer stage WST1 on which wafer W is mounted, wafer stage device 50 including WST2, and a control system for these components.
The lighting system 10 is disclosed, for example, in U.S. patent application publication No. 2003/0025890, and includes: a light source, an illumination uniformizing optical system including an optical integrator and the like, and an illumination optical system having a reticle blind and the like (neither of which is shown). The illumination system 10 illuminates a slit-shaped illumination region IAR on a reticle R defined by a reticle blind (masking system) with illumination light (exposure light) IL at a substantially uniform illuminance. Here, for the illumination light IL, for example, ArF excimer laser light (wavelength 193nm) is used.
On reticle stage RST, reticle R having a pattern surface (lower surface in fig. 1) on which a circuit pattern or the like is formed is fixed by, for example, vacuum suction. Reticle stage RST is micro-driven in the XY plane by reticle stage driving system 11 (not shown in fig. 1, see fig. 6) including, for example, a linear motor or the like, and is driven in the scanning direction (Y-axis direction in the direction orthogonal to the paper surface in fig. 1) at a predetermined scanning speed.
The positional information (including the position in the θ z direction (θ z rotation amount) information) in the XY plane (moving surface) of reticle stage RST is detected at any time with an analysis capability of, for example, about 0.25nm by a reticle laser interferometer (hereinafter, referred to as "reticle interferometer") 16 that irradiates a distance measuring beam onto moving mirror 15 (actually, a Y moving mirror (or a retro-reflector) having a reflection surface orthogonal to the Y axis direction and an X moving mirror having a reflection surface orthogonal to the X axis direction) as shown in fig. 1. Further, to measure position information in at least a 3 degree-of-freedom direction of the reticle R, an encoder system such as disclosed in U.S. patent application publication No. 2007/0288121, for example, may be used in place of, or in combination with, the reticle interferometer 16.
The projection unit PU is held by a main frame (also referred to as a measurement frame) which is disposed below (on the Z side of) the reticle stage RST in fig. 1 and constitutes a part of a body (not shown). The projection unit PU includes a lens barrel 40 and a projection optical system PL including a plurality of optical components held by the lens barrel 40. The projection optical system PL is a refractive optical system including, for example, a plurality of modules (lens modules) arranged along an optical axis AX parallel to the Z-axis direction. The projection optical system PL is, for example, telecentric on both sides and has a predetermined projection magnification (for example, 1/4 times, 1/5 times, 1/8 times, or the like). Therefore, when the illumination area IAR is illuminated with the illumination light IL from the illumination system 10, that is, by the illumination light IL of the reticle R arranged so that the pattern surface thereof substantially coincides with the 1 st surface (object surface) of the projection optical system PL, a reduced circuit pattern image (reduced image of a part of the circuit pattern) of the reticle R in the illumination area IAR is formed on the area (exposure area) IA conjugate to the illumination area IAR on the wafer W arranged on the 2 nd surface (image surface) side of the projection optical system PL and coated with a resist (sensitive agent) on the surface thereof through the projection optical system PL. Next, by synchronously driving reticle stage RST and wafer stages WST1 and WST2, reticle R is moved in the scanning direction (Y-axis direction) with respect to illumination area IAR (illumination light IL), and wafer W is moved in the scanning direction (Y-axis direction) with respect to exposure area IA (illumination light IL), so that scanning exposure of one illumination area (divided area) on wafer W is performed, and the pattern of reticle R is transferred to the illumination area. That is, the present embodiment generates a pattern of the reticle R on the wafer W by the illumination system 10 and the projection optical system PL, and forms the pattern on the wafer W by exposing the sensitive layer (resist) on the wafer W with the illumination light IL.
The main frame may be of a gate type conventionally used and a suspension support type such as that disclosed in U.S. patent application publication No. 2008/0068568.
Around the-Z-side end of the lens barrel 40, for example, a scale plate 21 is disposed at approximately the same height as the lower end surface of the lens barrel 40 and parallel to the XY plane. The scale plate 21, in the present embodiment, as shown in fig. 2, is composed of four L-shaped parts (parts) 211、212、213、214the-Z-side end of the lens barrel 40 is inserted into, for example, a rectangular opening 21a formed in the center thereof. Here, the X-axis of the scale plate 21Widths in the directions a and b and in the Y-axis direction of the opening 21a are ai and bi, respectively.
As shown in fig. 1, a scale plate 22 is disposed on substantially the same plane as the scale plate 21 at a position apart from the scale plate 21 in the + X direction. The scale plate 22, as shown in FIG. 3, is also formed of four L-shaped parts (parts) 221、222、223、224the-Z-side end of the alignment system ALG described later is inserted into, for example, a rectangular opening 22a formed in the center thereof. The widths of the scale plate 22 in the X-axis direction and the Y-axis direction are a and b, respectively, and the widths of the opening 22a in the X-axis direction and the Y-axis direction are ai and bi, respectively. In the present embodiment, the widths of the scale plates 21 and 22 and the widths of the openings 21a and 22a in the X-axis and Y-axis directions are the same, respectively, but the widths do not necessarily have to be the same, and may be different in at least one of the X-axis and Y-axis directions.
In the present embodiment, the scale plates 21, 22 are suspended from a not-shown main frame (measurement frame) for supporting the projection unit PU and the alignment system ALG. A reflection type two-dimensional diffraction grating RG (see fig. 2, 3, and 4) is formed on the lower surface (-Z side surface) of the scale plates 21 and 22, and is composed of a grating having a predetermined pitch, for example, 1 μm, in which the periodic direction is a 45-degree direction with respect to the X axis (a-45-degree direction with respect to the Y axis), and a grating having a predetermined pitch, for example, 1 μm, in which the periodic direction is a-45-degree direction with respect to the X axis (a-135-degree direction with respect to the Y axis). However, in the configuration of the two-dimensional diffraction grating RG and the encoder head described later, the portions 21 constituting the scale plates 21 and 22 are formed1To 214、221To 224The vicinity of the outer edge of each of the regions includes a non-effective region having a width t. The two-dimensional diffraction gratings RG of the scale plates 21 and 22 respectively cover the movement ranges of the wafer stages WST1 and WST2 at least during the exposure operation and during the alignment (measurement).
As shown in fig. 1, wafer stage device 50 includes: stage base 12 supported substantially horizontally on the floor surface by a plurality of (for example, three or four) vibration-proof mechanisms (not shown), wafer stages WST1 and WST2 arranged on stage base 12, wafer stage drive system 27 (only a part of which is shown in fig. 1, see fig. 6) for driving wafer stages WST1 and WST2, and a measurement system for measuring the positions of wafer stages WST1 and WST 2. The measurement system includes encoder systems 70 and 71 and a wafer laser interferometer system (hereinafter simply referred to as a wafer interferometer system) 18 shown in fig. 6. The encoder systems 70 and 71 and the wafer interferometer system 18 are left to be described later. However, in the present embodiment, the wafer interferometer system 18 is not necessarily provided.
As shown in fig. 1, stage base 12 is formed of a member having a flat plate-like outer shape, and the flatness of the upper surface thereof is extremely high so as to serve as a guide surface when wafer stages WST1 and WST2 move. Inside stage base 12, a coil unit including a plurality of coils 14a arranged in a matrix shape with the XY two-dimensional direction as the row direction and the column direction is housed.
Further, another base member for supporting this in a floating manner may be provided separately from the stage base 12, and may have a function of a counter mass (reaction force canceller) for moving the stage base 12 in accordance with the law of conservation of momentum due to the reaction force of the driving force of the wafer stages WST1, WST 2.
As shown in fig. 1, wafer stage WST1 includes: stage main body 91, and wafer table WTB1 arranged above stage main body 91 and supported by stage main body 91 in a noncontact manner by a Z tilt drive mechanism not shown. In this case, the wafer table WTB1 is supported in a noncontact manner by adjusting the balance between an upward force (repulsive force) such as an electromagnetic force and a downward force (attractive force) including its own weight at 3 points by the Z tilt driving mechanism, and is driven in a 3-degree-of-freedom direction at least in the Z-axis direction, the θ x direction, and the θ y direction. A slider 91a is provided at the bottom of the stage body 91. The slider portion 91a includes a magnet unit including a plurality of magnets arranged in an XY plane in an XY two-dimensional manner, a housing for housing the magnet unit, and a plurality of air bearings provided around the bottom surface of the housing.
The wafer W is loaded on the wafer table WTB1 through a wafer holder (not shown) and fixed by a chuck mechanism (not shown) by, for example, vacuum suction (or electrostatic suction). Although not shown, a 1 st fiducial mark plate and a 2 nd fiducial mark plate are provided on a wafer table WTB1 at a diagonal line with a wafer holder interposed therebetween. A plurality of reference marks to be detected by the pair of reticle alignment systems 13A and 13B and the alignment system ALG described later are formed on the reference mark plates 1 and 2, respectively. Here, the positional relationship of the plurality of reference marks of the 1 st and 2 nd reference mark plates is known.
Wafer stage WST2 has the same configuration as wafer stage WST 1.
Encoder systems 70 and 71 are configured to obtain (measure) positional information of wafer stages WST1 and WST2 in the 6-degree-of-freedom directions (X, Y, Z, θ x, θ y, and θ z) in an exposure time movement region including a region directly below projection optical system PL and a measurement time movement region including a region directly below alignment system ALG, respectively. Here, the configurations of the encoder systems 70 and 71 and the like are described in detail. The exposure time moving region (1 st moving region) is a region in which the wafer stage moves during an exposure operation in the exposure station (1 st region) where the wafer is exposed through the projection optical system PL, and the exposure operation includes, for example, not only exposure of all the irradiation regions of the pattern to be transferred on the wafer but also a preparatory operation for performing the exposure (for example, detection of the reference mark). The measurement time shift area (2 nd shift area) is an area where the wafer stage moves during the measurement operation in the measurement station (2 nd area) where the alignment system ALG detects the wafer alignment marks and measures the positional information thereof, and the measurement operation includes not only the detection of a plurality of alignment marks of the wafer but also the detection of reference marks by the alignment system ALG (and the measurement of the wafer positional information (step information) in the Z-axis direction), for example.
As shown in the plan views of fig. 2 and 3, encoder heads (hereinafter, referred to as heads) 60 are disposed at four corners of the top surface of each of the wafer tables WTB1 and WTB21～604. Here, the read head 601、602Separation distance in the X-axis direction from the read head 603、604In the X-axis directionThe separation distances are equal to each other by a. Furthermore, the read head 601、604Separation distance in Y-axis direction from the head 602、603The separation distances in the Y-axis direction are equal to each other by B. These separation distances A, B are larger than the widths ai and bi of the opening 21a of the scale plate 21. Strictly speaking, considering the width t of the non-effective region, A ≧ ai +2t and b ≧ bi +2 t. Read head 601～604A head 60 as represented in FIG. 41For example, the wafer tables WTB1 and WTB2 are housed in holes formed therein at a predetermined depth in the Z-axis direction.
As shown in FIG. 5, the read head 601A two-dimensional reading head having a 135-degree direction (i.e., -45-degree direction with respect to the X-axis) with respect to the X-axis and a Z-axis as a measurement direction. Similarly, the read head 602～604Also, the two-dimensional head is provided with a 225-degree direction (i.e., a 45-degree direction with respect to the X-axis) and a Z-axis direction with respect to the X-axis, a 315-degree direction (i.e., -45-degree direction with respect to the X-axis) and a Z-axis direction with respect to the X-axis, and a 45-degree direction and a Z-axis direction with respect to the X-axis as measurement directions, respectively. Read head 601～604As can be seen from fig. 2 and 4, the portions 21 of the scale plate 21 facing each other are opposed to each other1～214Or portion 22 of scale plate 221～224The two-dimensional diffraction grating RG formed on the surface irradiates the measurement beam, receives the reflected and diffracted beams from the two-dimensional diffraction grating, and measures the positions of wafer tables WTB1 and WTB2 (wafer stages WST1 and WST2) in the respective measurement directions. Here, the read head 60 is provided1～604For example, a sensor head having the same configuration as that of the displacement measuring sensor head disclosed in U.S. Pat. No. 7,561,280 can be used.
The reading head 60 configured as described above1～604Since the optical path length of the measuring beam in the air is extremely short, the influence of air fluctuation can be almost ignored. However, in the present embodiment, the light source and the photodetector are provided outside each head, specifically, inside (or outside) the stage body portion 91, and only the optical system is provided inside each head. While the light sourceAnd the photodetector and the optical system are optically connected via an optical fiber, not shown. In order to improve the positioning accuracy of wafer table WTB (fine movement stage), it is also possible to perform aerial transmission of laser light or the like between stage body portion 91 (coarse movement stage) and wafer table WTB (fine movement stage) (hereinafter, simply referred to as coarse and fine movement stage), or to provide a reading head on stage body portion 91 (coarse movement stage), measure the position of stage body portion 91 (coarse movement stage) with the reading head, and measure the relative displacement between coarse and fine movement stages with another sensor.
When wafer stages WST1 and WST2 are located within the exposure time movement region, head 601Is configured as a pair of (parts 21 of) scale boards 211) A two-dimensional encoder 70 for irradiating a measuring beam (measuring light), receiving a diffracted beam from a grating formed on the surface (lower surface) of the scale plate 21 and having a 135-degree direction with respect to the X axis, that is, a-45-degree direction with respect to the X axis (hereinafter, simply referred to as the-45-degree direction), and measuring the positions of the wafer tables WTB1, WTB2 in the-45-degree direction and the Z-axis direction1、711(refer to fig. 6). Similarly, the read head 602～604Respectively constituting (parts 21 of) the scale plate 212～214) A two-dimensional encoder 70 for irradiating a measuring beam (measuring light), receiving diffracted light beams from a grating formed on a surface (lower surface) of the scale plate 21 and having a 225-degree direction with respect to the X axis, that is, a + 45-degree direction with respect to the X axis (hereinafter, simply referred to as a 45-degree direction), a 315-degree direction, that is, a-45-degree direction with respect to the X axis, and a 45-degree direction as a periodic direction, and measuring positions of the wafer tables WTB1, WTB2 in the 225-degree (45-degree) direction and the Z-axis direction, a 315-degree (-45-degree) direction and the Z-axis direction, and a 45-degree direction and the Z-axis direction2～704、712～714(refer to fig. 6).
When wafer stages WST1 and WST2 are located within the measurement time movement region, head 60 is moved to the measurement time movement region1Is configured as a pair of (parts 22 of) scale plates 221) Two-dimensional encoder 70 that irradiates a measuring beam (measuring light) and receives a diffracted beam from a grating having a periodic direction of 135 degrees (-45 degrees) as a periodic direction1、711(refer to fig. 6).
Encoder (hereinafter, referred to simply as encoder as appropriate) 701～704、711～714To the main control device 20 (see fig. 6). The main control device 20 is based on a scale plate 21 (a component 21) formed with a two-dimensional diffraction grating RG1～214) The measurement values of at least three encoders (that is, at least three encoders that output valid measurement values) facing each other on the lower surface determine the position information of wafer tables WTB1, WTB2 in an exposure time shift region including a region immediately below projection optical system PL. Similarly, main control device 20 is based on a scale plate 22 (constituting part 22) on which a two-dimensional diffraction grating RG is formed1～224) The measurement values of at least three encoders facing each other on the lower surface (that is, at least three encoders outputting valid measurement values) determine the positional information of the wafer tables WTB1 and WTB2 in the measurement time shift area including the area immediately below the alignment system ALG.
In exposure apparatus 100 of the present embodiment, the positions of wafer stages WST1 and WST2 (wafer tables WTB1 and WTB2) can be measured separately and independently from encoder systems 70 and 71 by wafer interferometer system 18 (see fig. 6). The measurement result of the wafer interferometer system 18 is used for a backup in a case where a long-term variation (for example, due to a temporal deformation of the scale) in the measurement values of the encoder systems 70 and 71 is corrected (corrected) or in a case where an output of the encoder systems 70 and 71 is abnormal, or the like, in an auxiliary manner. Here, a detailed description of the wafer interferometer system 18 is omitted.
As shown in fig. 1, the alignment system ALG is an off-axis alignment system disposed at a predetermined interval on the + X side of the projection optical system PL. In the present embodiment, as the alignment system ALG, for example, a fia (field Image alignment) system is used, which illuminates a mark with a broadband light such as a halogen lamp, and aligns a sensor by performing Image processing on an Image of the mark to measure a mark position. The photographing signal from the alignment system ALG is supplied to the main control apparatus 20 (see fig. 6) through an alignment signal processing system (not shown).
The alignment system ALG is not limited to the FIA system, and may be an alignment sensor that detects scattered light or diffracted light generated from a mark by irradiating coherent (coherent) detection light to the mark, or by detecting two diffracted lights generated from the mark by interference (for example, diffracted lights of the same order or diffracted lights diffracted in the same direction), alone or in an appropriate combination. As the alignment system ALG, an alignment system having a plurality of detection regions as disclosed in, for example, U.S. patent application publication No. 2008/0088843 and the like can also be used.
The exposure apparatus 100 of the present embodiment is provided with a multi-point focus position detection system (hereinafter, simply referred to as a multi-point AF system) AF (not shown in fig. 1, see fig. 6) of an oblique incidence system (not shown in fig. 1) which is disposed in a measurement station together with the alignment system ALG and has the same configuration as that disclosed in, for example, U.S. Pat. No. 5,448,332. At least a part of the measurement operation by the multi-spot AF system AF is performed in parallel with the mark detection operation by the alignment system ALG, and the encoder system is used to measure the position information of the wafer table during the measurement operation. The detection signal of the multi-point AF system AF is supplied to the main control device 20 (refer to FIG. 6) through an AF signal processing system (not shown). The main controller 20 detects position information (step information/irregularity information) in the Z-axis direction of the surface of the wafer W based on the detection signal of the multi-spot AF system AF and the measurement information of the encoder system, and performs so-called focus/leveling control of the wafer W during scanning exposure based on the pre-detection information and the measurement information of the encoder system (position information in the Z-axis, θ x, and θ y directions). Further, a multipoint AF system may be provided in the exposure station in the vicinity of the projection unit PU, and the wafer stage may be driven while measuring positional information (concave-convex information) on the wafer surface during the exposure operation, thereby performing focus and leveling control of the wafer W.
In the exposure apparatus 100, a pair of reticle alignment systems 13A and 13B (not shown in fig. 1, see fig. 6) of the ttr (throughput high tilt) system using light of an exposure wavelength, for example, disclosed in specification No. 5,646,413, are further provided above the reticle R. The detection signals of the reticle alignment systems 13A, 13B are supplied to the main control apparatus 20 via an alignment signal processing system not shown. In place of the reticle alignment system, an aerial image measuring instrument, not shown, provided on wafer stage WST may be used to perform reticle alignment.
Fig. 6 is a partially omitted block diagram of a control system related to stage control of the exposure apparatus 100. This control system is configured with a main control device 20 as a center. The main controller 20 includes a so-called microcomputer (or a workstation) including a CPU (central processing unit), a ROM (read only memory), a RAM (random access memory), and the like, and collectively controls the entire apparatus.
In the exposure apparatus 100 configured as described above, at the time of manufacturing a module, the main control apparatus 20 moves one of the wafer stages WST1 and WST2 on which a wafer is mounted in the measurement station (measurement time movement area) to perform a wafer measurement operation using the alignment system ALG and the multi-spot AF system. That is, the mark detection using the alignment system ALG, the so-called wafer alignment (for example, full wafer enhanced alignment (EGA) disclosed in U.S. patent No. 4,780,617 and the like), and the measurement of the wafer surface information (step/unevenness information) using the multi-point AF system are performed on the wafer W held on one of the wafer stages WST1 and WST2 in the measurement time movement area. At this time, the encoder system 70 (encoder 70) is used1～704) Or encoder system 71 (encoder 71)1～714) Position information in the 6-degree-of-freedom directions (X, Y, Z, θ x, θ y, and θ z) of wafer stages WST1 and WST2 is obtained (measured).
After the measurement operation such as wafer alignment, one of the wafer stages (WST1 or WST2) is moved to the exposure time movement region, and the main controller 20 performs reticle alignment or the like using the reticle alignment systems 13A and 13B, a reference mark plate (not shown) on the wafer table (WTB1 or WTB2), and the like, in the same program as that of a general scanning stepper (for example, the program disclosed in U.S. Pat. No. 5,646,413 specification or the like).
Then, by the master controlThe apparatus 20 performs an exposure operation of a step-and-scan method based on the measurement results of wafer alignment and the like, and transfers the pattern of the reticle R to each of a plurality of shot regions on the wafer W. The step-and-scan type exposure operation is performed by alternately repeating a scanning exposure operation in which the reticle stage RST and the wafer stage WST1 or WST2 are moved in synchronization with each other, and an inter-irradiation movement (stepping) operation in which the wafer stage WST1 or WST2 is moved to an acceleration start position at which exposure of the irradiation region is performed. During the exposure operation, the encoder system 70 (encoder 70) is used1～704) Or encoder system 71 (encoder 71)1～714) Position information in the 6-degree-of-freedom direction (X, Y, Z, thetax, thetay, thetaz) of one wafer stage (WST1 or WST2) is obtained (measured).
Further, exposure apparatus 100 of the present embodiment includes two wafer stages WST1 and WST 2. Therefore, a parallel processing operation is performed, in which wafer alignment or the like is performed on a wafer mounted on the other wafer stage WST2 in parallel with step-and-scan exposure of one wafer stage, for example, a wafer mounted on wafer stage WST 1.
As described above, in exposure apparatus 100 of the present embodiment, main controller 20 obtains (measures) positional information of wafer stage WST1 in the 6-degree-of-freedom direction (X, Y, Z, θ x, θ y, θ z) using encoder system 70 (see fig. 6) in both the exposure time movement area and the measurement time movement area. In addition, main controller 20 obtains (measures) position information of wafer stage WST2 in the 6-degree-of-freedom direction (X, Y, Z, θ x, θ y, θ z) using encoder system 71 (see fig. 6) in both the exposure time movement area and the measurement time movement area.
Next, the principle of position measurement in the 3-degree-of-freedom direction (X-axis direction, Y-axis direction, and θ z direction (also abbreviated as X, Y, θ z)) in the XY plane using the encoder systems 70 and 71 will be described further. Here, the encoder readhead 601～604Or encoder 701～704The measurement result or measurement value of (2) is an encoder reading head601～604Or encoder 701～704Is measured in a direction other than the Z-axis direction.
Similarly, when wafer stage WST1 is in the exposure time movement area and is located at the-X side and + Y side areas with respect to exposure center P (area in quadrant 2 with exposure center P as the origin, however, area A is not included0)2 nd region A of2Inner, read head 601、602、603Portions 21 respectively opposed to the scale plate 211、212、213. When wafer stage WST1 is in the exposure time movement area and is located at the-X side and the-Y side relative to the exposure center P (the area in quadrant 3 with the exposure center P as the origin, however, does not include area A)0) Region 3A of)3Inner, read head 602、603、604Portions 21 respectively opposed to the scale plate 212、213、214. When wafer stage WST1 is in the exposure time movement area and is located at the + X side and the-Y side relative to the exposure center P (the area in quadrant 4 with the exposure center P as the origin, however, does not include area A)0) 4 th region A of (B)4Inner, read head 603、604、601Portions 21 respectively opposed to the scale plate 213、214、211。
In this embodiment, the encoder readhead 60 is not limited to that described above1～604And the conditions (A ≧ ai +2t, B ≧ bi +2t) for the configuration and arrangement of the scale plate 21, the conditions A ≧ ai + W +2t, B ≧ bi + L +2t are added, taking into account the size (W, L) of the irradiation region for forming the pattern on the wafer. Here, W, L denotes the widths of the irradiation region in the X axis direction and the Y axis direction, respectively. W, L are respectively equal to the distance between the scanning exposure sections and the distance of the step in the X-axis direction. Under such conditions, as shown in fig. 7 and 13, when wafer stage WST1 is positioned in cross-shaped area a centered on exposure center P0(region including a region having a width A-ai-2 t in the longitudinal direction along the Y-axis passing through the exposure center P and a region having a width B-bi-2 t in the longitudinal direction along the X-axis (hereinafter, referred to as "0 th region")) All of heads 60 on wafer stage WST11～604Opposite the scale plate 21 (corresponding portion 21)1～214). Thus, in the 0 th region A0From all of the read heads 601～604(encoder 70)1～704) The valid measurement values are sent to the main control device 20. In addition to the above conditions (a ≧ ai +2t, B ≧ bi +2t), in the present embodiment, conditions a ≧ ai + W +2t, and B ≧ bi + L +2t may be added in consideration of the size (W, L) of the irradiation region on the wafer on which the pattern is formed. Here, W, L denotes the widths of the irradiation region in the X axis direction and the Y axis direction, respectively. W, L are equal to the distance between the scanning exposure zones and the step distance in the X-axis direction.
Master control device 20 according to read head 601～604(encoder 70)1～704) The position (X, Y, θ z) of wafer stage WST1 in the XY plane is calculated as a result of the measurement of (a). Here, the encoder 701～704The measurement values of (each is denoted as C)1～C4) As shown in expressions (1) to (4), the position depends on the position (X, Y, θ z) of wafer stage WST 1.
C1＝－(cosθz+sinθz)X/√2
+(cosθz－sinθz)Y/√2+√2psinθz…(1)
C2＝－(cosθz－sinθz)X/√2
－(cosθz+sinθz)Y/√2+√2psinθz…(2)
C3＝(cosθz+sinθz)X/√2
－(cosθz－sinθz)Y/√2+√2psinθz…(3)
C4＝(cosθz－sinθz)X/√2
+(cosθz+sinθz)Y/√2+√2Psinθz…(4)
As shown in fig. 5, p is a distance from the center of the wafer table WTB1(WTB2) in the X-axis and Y-axis directions of the head.
Main control apparatus 20 is based on area A where wafer stage WST1 is located0～A4Three heads (encoders) facing the scale plate 21 are specified, a connected cubic program is combined by selecting the expression based on the measurement values from the above expressions (1) to (4), and the positions (X, Y, θ z) of the wafer stage WST1 in the XY plane are calculated by using the disconnected cubic program from the measurement values of the three heads (encoders). For example, wafer stage WST1 is located in area A11In the internal case, the master control device 20 slave heads 601、602、604(encoder 70)1、702、704) The measurement values of the read heads are combined with the cubic program according to the formulas (1), (2) and (4), and the measurement values of the read heads are substituted into the left side of the formulas (1), (2) and (4) to disconnect the cubic program.
In addition, when wafer stage WST1 is located in area 0A0In the internal case, the master control device 20 slave heads 601～604(encoder 70)1～704) Any three of them can be selected. For example, after wafer stage WST1 moves from region 1 to region 0, head 60 corresponding to region 1 is selected1、602、604(encoder 70)1、702、704) And (4) finishing.
Based on the calculation results (X, Y, θ z), main controller 20 drives wafer stage WST1 within the exposure time movement area (performs position control).
When wafer stage WST1 is located within the measurement time movement area, main control apparatus 20 measures positional information in the 3-degree-of-freedom direction (X, Y, θ z) using encoder system 70. Here, regarding the measurement principle and the like, (the portion 21 of) the scale plate 21 except for the exposure center P is replaced with the detection center of the alignment system ALG1～214) Replaced by (part 22 of) scale plate 221～224) This is also true for the case where wafer stage WST1 is located in the previous exposure time movement region.
Further, main controller 20 controls the wafer stage WST1 and WST2,a reading head 60 to be opposed to the scale plates 21, 221～604And switching to at least one different three for use. Here, when switching the encoder heads, a subsequent process is performed to ensure continuity of the wafer stage position measurement results as disclosed in, for example, U.S. patent application publication No. 2008/0094592.
Next, the head 60 in the step-and-scan exposure operation will be described1～604Switching and continuing processing.
As an example 1, a pair of wafers W shown in FIG. 7 is treated1The exposure operation of (2) will be described. Here, in the wafer W1For example, as shown in fig. 8 in an enlarged scale, a total of 36 irradiation regions S in which even numbers and odd numbers are arranged in the X-axis direction and the Y-axis direction1～S36。
To wafer W1The step-and-scan exposure is performed along the path shown in fig. 9. The path in fig. 9 shows a trajectory of the exposure center (center of exposure area IA) P passing through each irradiation area. The solid line portion in this trajectory indicates the movement trajectory of the exposure center P during scanning exposure of each irradiation region, and the dotted line portion (dotted line portion) indicates the trajectory of the exposure center P in real time during the step movement between the irradiation regions adjacent to each other in the scanning direction and the non-scanning direction. Although the exposure center P is actually fixed and the wafer moves in the opposite direction to the path of fig. 9, for the convenience of description in this specification, it is assumed that the center moves relative to the fixed wafer.
Exposure apparatus 100 and head 60 of the present embodiment1～604Three of the three sides facing the scale plate 21 are switched to be used according to the position of the wafer stage WST 1. Therefore, in wafer stage WST1, area a shown in fig. 7 is covered1～A4Via the area a0When moving to another region, the head to be used is switched. Thus, the wafer W is shown in FIG. 91The area B corresponding to the head group facing the scale plate 21 when the locus of the upper exposure center P overlaps and the wafer stage WST1 is located at the position of the exposure center P in the locus0～B4。
Region B in FIG. 90～B4Corresponding to movement areas A of wafer stage WST1 in FIG. 70～A4. For example, during scanning exposure of an irradiation region in region Bi or during stepping movement to the next irradiation region, wafer stage WST1 moves within region Ai. Therefore, the exposure center P is located in the region B1Inner, is the read head 604、601、602Opposite the scale plate 21. Similarly, the exposure center P is located in the region B2、B3、B4And B0When inside, it is the read head 60 respectively1、602、603Reading head 602、603、604Reading head 603、604、601And a full read head 601～604Opposite the scale plate 21.
As described above, the exposure center P moves on the trajectory shown in fig. 9 by the scanning exposure of the irradiation region or the stepping movement between the irradiation regions, and moves from the region B1～B4Via the region B0When moving to another region, the head to be used is switched. Therefore, in FIG. 9, the wafer W is treated1The occurrence position of the read head switching is indicated by a double-layer circle.
For example, first, the exposure center P is in the 1 st irradiation region S1Irradiation region S of No. 33Performing exposure processing to obtain a second region B1To region B0After moving, the circle C is aligned1Region B shown inside0Inner 4 th irradiation region S4After exposure treatment, the substrate is transferred to the region B2Inner 5 th irradiation region S5When the head is moved in steps, the switching of the head (1 st switching) occurs. Here, as described above, the exposure center P is located in the region B1、B0、B2Internal, respectively, are read heads 604、601、602Full read head 601～604Reading head 601、602、603Opposite the scale plate 21. Thus, the 1 st switching read head to be usedSlave read head 604、601、602Switched to the read head 601、602、603。
FIG. 10(A) is a circle C in FIG. 9 for illustrating the 1 st switching in detail1The enlarged view of the inside shows a temporal change in velocity Vy of wafer stage WST1 in the Y-axis direction before and after the 1 st switch in fig. 10 (B).
FIG. 10(A) is a circle C in FIG. 9 for illustrating the 1 st switching in detail1The enlarged view of the inside shows a temporal change in velocity Vy of wafer stage WST1 in the Y-axis direction before and after the 1 st switch in fig. 10 (B).
The main controller 20 is in the 3 rd irradiation area S3After exposure, the head 60 is used4、601、602(encoder 70)4、701、702) The measurement result of (4) is obtained by driving (position controlling) wafer stage WST1 so that exposure center P moves to the 4 th irradiation region S4Acceleration start position e4 of exposure. When exposure center P reaches acceleration start position e4, main controller 20 starts wafer stage WST1 (wafer W)1) Moves in synchronization with reticle stage RST (reticle R). That is, main controller 20 accelerates and drives wafer stage WST1, and at the same time, drives reticle stage RST in a manner that is opposite to wafer stage WST1 and at a speed that is the inverse of projection magnification β of the speed of wafer stage WST1, and tracks the operation of wafer stage WST 1. As shown in fig. 10B, after the acceleration time Ta elapses from the start of acceleration (time t4), the velocities of both stages WST1 and RST are constant.
The main controller 20 is in the 3 rd irradiation area S3After exposure, the head 60 is used4、601、602(encoder 70)4、701、702) The measurement result of (4) is obtained by driving (position controlling) wafer stage WST1 so that exposure center P moves to the 4 th irradiation region S4Acceleration start position e4 of exposure. When exposure center P reaches acceleration start position e4, main controller 20 starts wafer stage WST1 (wafer W)1) And the marked lineSynchronous movement of sheet stage RST (reticle R). That is, main controller 20 accelerates and drives wafer stage WST1, and at the same time, drives reticle stage RST in a manner that is opposite to wafer stage WST1 and at a speed that is the inverse of projection magnification β of the speed of wafer stage WST1, and tracks the operation of wafer stage WST 1. As shown in fig. 10B, after the acceleration time Ta elapses from the start of acceleration (time t4), the velocities of both stages WST1 and RST are constant.
During a settling time Tb from the end of acceleration to the start of exposure, main controller 20 performs tracking drive of reticle stage RST on wafer stage WST1 until wafer W1The displacement error with respect to the reticle R has a predetermined relationship (substantially zero).
After a settling time Tb, main controller 20 responds to heads 604、601、602(encoder 70)4、701、702) Wafer stage WST1 is driven at a constant speed. Thus, during exposure time Tc, exposure area IA (exposure center P) is located from irradiation area S as shown in fig. 10 a4the-Y end of the light source moves to the + Y end at the same speed to irradiate the area S4Is scanned and exposed. In the scanning exposure, the wafer W1The constant-speed synchronous movement state with the reticle R is maintained.
After the end of exposure, during a constant velocity overscan time (post-settling time) Td, wafer stage WST1 moves at a constant velocity. During this period, as shown in fig. 10(a), the exposure center P passes through the irradiation region S at a constant speed4Side + Y the 1 st switching position P1. At this time, the master controller 20 uses the head slave 604、601、602(encoder 70)4、701、702) Switched to the read head 601、602、603(encoder 70)1、702、703). At this time, main controller 20 performs the subsequent processing in order to ensure continuity of the position measurement results of wafer stage WST1 before and after switching. That is, the master controller 20 controls the slave heads 601、602、603Crystal for measuring value ofPosition measurement results (X ', Y ', θ z ') of wafer stage WST1 and slave head 604、601、602Measurement results (X, Y, θ z) of wafer stage WST1 obtained from the measurement values are matched, and head 60 newly used after the reset switching is performed3Measured value C of3. Details of this subsequent processing are left to be described later.
After the switching, during the deceleration overscan time Te, the main control device 20 controls the head 601、602、603(encoder 70)1、702、703) The measurement result of (3) is subjected to deceleration driving of wafer stage WST 1. At the same time, reticle stage RST is also decelerated. At the deceleration overscan time Te, wafer stage WST1 also moves in the X-axis direction in parallel with the movement in the Y-axis direction. Thus, the exposure center P is from the irradiation region S4The + Y end of the first and second electrodes is directed to the region B in a U-shaped track2Inner next irradiation area S5And (4) moving in steps.
After the deceleration of wafer stage WST1 is completed, main controller 20 continues to drive wafer stage WST1 and reticle stage RST in the same manner as before, but drives wafer stage WST1 and reticle stage RST in opposite directions, respectively, and causes next irradiation area S to be illuminated5And (6) exposing.
The measurement results of the encoder systems 70 and 71 include measurement errors due to manufacturing errors of the scale.
Next, in order to simply explain the principle of the head switching and the connection process, the four heads are also abstractly described as Enc1, Enc2, Enc3, and Enc 4.
Fig. 11 a shows (tracks of) temporal changes in position coordinates (X, Y, θ z) of wafer stage WST1 calculated from the measurement values of encoders Enc1, Enc2, and Enc3 and in position coordinates (X ', Y ', θ z ') of wafer stage WST1 calculated from the measurement values of encoders Enc2, Enc3, and Enc4 before and after switching from heads (encoders) Enc1, Enc2, Enc3 to encoders Enc2, Enc3, and Enc 4. Measurement error due to scale manufacturing error, and position measurement of wafer stage WST1The trajectory of the fruit will oscillate minutely. Therefore, for example, a simple connection process disclosed in U.S. patent application publication No. 2008/0094592, etc., incorporates the measurement error and resets the measurement value of the newly used encoder Enc4 (here, the head 60)4Measured value C of4). This embodiment employs a sequential process that does not generate such a state.
Next, the principle of the subsequent processing performed by the exposure apparatus 100 of the present embodiment will be described. In the present embodiment, the position coordinates of wafer stage WST1 are controlled by main controller 20 at time intervals of, for example, 96 μ sec. At each control sampling interval, the position servo control system (part of main control device 20) updates the current position of wafer stage WST1, calculates a thrust command value or the like to be positioned at the target position, and outputs the result to wafer stage drive system 27. As described above, the current position of wafer stage WST1 is determined from head 60 constituting encoder system 701～604(encoder 70)1～704) Three measurements of (1) were calculated. The measurement values of these read heads (encoders) are monitored at time intervals (measurement sampling intervals) that are much shorter than the control sampling intervals.
Fig. 12 shows drive (position control) of wafer stage WST and head 60 based on the measurement result of encoder system 701～604(encoder 70)1～704) And the following processing accompanying the switching. In fig. 12, reference symbol CSCK denotes a generation timing of a sampling frequency (control frequency) for position control of wafer stage WST1, and reference symbol MSCK denotes a generation timing of a sampling frequency (measurement frequency) for measurement by an encoder.
The master control device 20 monitors the measured values of the encoder system 70 (the four encoders Enc1, Enc2, Enc3, Enc4 constituting this) at each control frequency (CSCK).
The encoders Enc1, Enc2, Enc3, Enc4 correspond to the heads 60, respectively, at the 1 st switching time4、601、602、603(encoder 70)4、701、702、703)。
In controlling the frequency, main control device 20 calculates the position coordinates (X, Y, θ z) of wafer stage WST1 from the measured values of encoders Enc1, Enc2, and Enc3 using the connected cubic program constituted by corresponding equations (1) to (3), and also calculates the position coordinates (X ', Y ', θ z ') of wafer stage WST1 from the measurement values of encoders Enc2, Enc3, and Enc4 used after switching, as in the case of the 1 st control frequency.
Main control device 20 to irradiation area S4Until the scanning exposure (exposure time Tc) of (1) is finished, stage position coordinates (X, Y, θ z) calculated from the measurement values of encoders Enc1, Enc2, and Enc3 are output to wafer stage drive system 27 as stage coordinates for servo control, and wafer stage WST1 is driven. After the exposure is completed, at the 3 rd control frequency during the constant velocity overscan time (post settling time) Td, the main control device 20 switches the encoders Enc1, Enc2, Enc3 to the encoders Enc2, Enc3, Enc 4.
As shown in fig. 11(a), the continuity of the calculated stage position coordinates cannot be satisfied by a simple continuation process due to a measurement error caused by a scale manufacturing error or the like. Therefore, the main control device 20 is aligned with the irradiation area S4That is, for a part Q of the scanning exposure interval shown in fig. 10(a)1In parallel with the operation of driving wafer stage WST1 at the same speed, a preprocessing (also referred to as a "connection calculation") for performing a connection process is performed for each control frequency (CSCK). That is, as shown in fig. 12, the main controller 20 obtains the difference between the position coordinates (X, Y, θ z) and the position coordinates (X ', Y ', θ z '), and obtains the moving average MA of the difference with respect to the predetermined frequency number kK{ (X, Y, θ z) - (X ', Y ', θ z ') }, held as coordinate offset (offset) O. In FIG. 12, the symbol MA is used for calculation of moving averageKAnd (4) showing.
Further, the moving average MA may be obtained for each predetermined frequency number K of the position coordinates (X, Y, θ z) and the position coordinates (X ', Y', θ z ')/the position coordinates (X', Y ', θ z')K(X, Y, θ z) and MAK(X ', Y ', θ z '), and applying the equal difference MAK(X、Y、θz)－MAK(X ', Y ', θ z ') is held as a coordinate offset O.
The main controller 20 performs a connection process at the time of switching. That is, main control device 20 adds coordinate offset O held at the time of the previous 2-th control frequency to the position coordinates (X ', Y ', θ z ') of wafer stage WST1 calculated from the measurement values of encoders Enc2, Enc3, and Enc4 at the 3-th control frequency so as to match the position coordinates (X, Y, θ z) of wafer stage WST1 calculated from the measurement values of encoders Enc1, Enc2, and Enc3 at the time of the previous control frequency (in this case, at the time of the 2-th control frequency). The measured value of the encoder Enc4 is calculated by substituting the offset-corrected position coordinates { (X ', Y ', θ z ') + O } into any of equations (1) to (4) based on the measured value of the encoder Enc4, and is set as the measured value of the encoder Enc 4. In fig. 12, this subsequent processing is denoted by symbol CH.
In the following process, it is necessary to confirm that the value of the coordinate offset O is sufficiently stable for the nearest predetermined frequency. As described above, due to measurement errors caused by scale manufacturing errors and the like, the position coordinates (X, Y, θ z) of wafer stage WST1 calculated from the measurement values of encoder system 70 slightly oscillate with respect to the true position. Therefore, it is preferable to perform the subsequent processing at a timing (when the frequency is generated) at which the difference between the position coordinates (X, Y, θ z) of wafer stage WST1 calculated from the measurement values of encoders Enc1, Enc2, and Enc3 and the position coordinates (X ', Y ', θ z ') of wafer stage WST1 calculated from the measurement values of encoders Enc2, Enc3, and Enc4 is sufficiently stable and coordinate offset O is matched or substantially matched.
By the above-described subsequent processing, continuity of the wafer stage position coordinates calculated before and after switching can be ensured as shown in fig. 11 (B).
Further, the following processing is not limited to the case of correcting the head measurement value after switching as described above, and there may be other processing, and these processes may be adopted. For example, other methods such as driving (position control) the wafer stage by adding an offset to the current position or the target position of the wafer stage using the measurement error as an offset, or correcting only the position of the reticle in which the measurement error is different may be applied.
After the switching, at the 4 th control frequency in fig. 12 and thereafter, main controller 20 outputs position coordinates (X ', Y ', θ z ') calculated from the measurement values of encoders Enc2, Enc3, and Enc4 to wafer stage drive system 27 as stage coordinates for servo control, and controls and drives wafer stage WST 1.
In addition, the 1 st switching is performed in the region B0Inner 4 th irradiation region S4After scanning exposure, toward the region B2Inner 5 th irradiation region S5Before the step movement, the head to be used is switched. Here, the wafer W shown in FIG. 71Of the irradiated area, as shown in FIG. 9, area B0Also includes a 3 rd irradiation region S3. Therefore, as shown in FIG. 10(C), the region B may be formed0Inner 3 rd irradiation region S3After the scanning exposure, the 4 th irradiation region S4Before the step movement, the head used is switched. In this case, the irradiation region S is aligned with3Part Q of the scanning exposure interval of (2)1' the operation of constant-speed-driving wafer stage WST1 is performed in parallel with the above-described continuing operation, and irradiation area S No. 3 is3After scanning exposure, wafer stage WST1 passes through irradiation area No. 3 at a constant speed3Is at the-Y side switching occurrence position P1' when, the read head 60 will be used4、601、602Switched to the read head 601、602、603. At this time, main controller 20 uses head 60 to be used for subsequent processes, that is, to be newly used after switching, in order to ensure continuity of the position measurement results of wafer stage WST1 before and after switching3Measured value C of3The coordinate offset O obtained by the successive calculation is used for resetting.
In the same manner as the above-described 1 st switching, the exposure center P is in the 7 th irradiation region S710 th irradiation region S10From the region B by exposure treatment2To region B0After moving, proceed to area B0Inner 11 th irradiation region S11To the region B by exposure1Inner 12 th irradiation region S12In the step movement, the head switching (2 nd switching) occurs. Here, the used slave readhead 601、602、603Switched to the read head 604、601、602。
Then, the wafer W is processed1A 15 th irradiation region S arranged in the X-axis direction at the center in the Y-axis direction1522 nd irradiation region S22In step-and-scan exposure, the exposure center P passes through the region B0In the region B1、B4Or region B2、B3And (4) moving. At this time, head switching (3 rd to 11 th switching) occurs. At the exposure center P via the region B0And in the region B1、B4Reading head for use in moving between 604、601、602And a read head 603、604、601To switch between in the region B2、B3The reading head used in the time of moving is at the reading head 601、602、603And a read head 602、603、604To switch between.
FIG. 10D shows a circle C in FIG. 9 for explaining the 8 th and 9 th switching representing the 3 rd to 11 th switching in detail2The inside is enlarged. From this FIG. 10(D), the 20 th irradiation region S20And the 21 st irradiation region S21(and other 15 th shot region S)1519 th irradiation region S1922 nd irradiation region S22) Is located in the region B0And (4) the following steps. Track crossing region B of exposure center P0And in the region B2、B3And (4) unfolding the components. That is, the exposure center P spans the region B0In the region B2、B3And go back and forth.
A main controller 20 for irradiating the area S at 19 th19After the exposure process of (2), according to the head 602、603、604(encoder 70)2、703、704) The measurement result of (2) is used to drive (position) wafer stage WST1Control) of the exposure center P toward the 20 th irradiation region S along a U-shaped path shown by a broken line in fig. 10(D)20And (4) moving in steps.
When the exposure center P reaches the acceleration start position during the stepping movement, main controller 20 starts wafer stage WST1 (wafer W)1) Acceleration (synchronous drive) with reticle stage RST (reticle R). After the acceleration time (Ta) elapses from the start of acceleration, the velocities of both stages WST1, RST are constant.
Further, during the exposure time (Tc) after the settling time (Tb), the main controller 20 controls the heads 602、603、604(encoder 70)2、703、704) Wafer stage WST1 is driven at the same speed as the measurement result of (a). Accordingly, the exposure center P moves at a constant speed along a straight path (scanning exposure path) indicated by a solid line in fig. 10D. That is, exposure area IA (exposure center P) is from irradiation area S20Moves to the-Y end at a constant speed to irradiate the region S20Is scanned and exposed.
Main control device 20 and the irradiation area S20In parallel to the scanning exposure of the irradiation region S20Part Q of the scanning exposure path of2The operation of constant velocity movement of wafer stage WST1 is performed in parallel with the above-described connection calculation. The main controller 20 irradiates the area S in the 20 th irradiation area20After scanning exposure, wafer stage WST1 passes through the 20 th irradiation region S at a constant speed20Is at the-Y side switching occurrence position P2The secondary readhead 60 to be used2、603、604Switched to the read head 601、602、603. At this time, main controller 20 uses head 60 to be newly used after switching in the above-described sequential process in order to ensure continuity of the position measurement results of wafer stage WST1 before and after switching1Measured value C of1The coordinate offset O obtained by the successive calculation is used for resetting.
After switching, the main controller 20 responds to the head 601、602、603(encoder 70)1、702、703) The measurement result of (a) is used to drive (position control) wafer stage WST1 to the next irradiation area S21And (4) moving in steps. At this time, the exposure center P is from the irradiation region S20The Y end of (A) depicts a U-shaped track, temporarily exits the area B2Then returns to the area B0Inward toward the next irradiation region S20。
When the exposure center P reaches the acceleration start position during the stepping movement, main controller 20 starts wafer stage WST1 (wafer W)1) Acceleration (synchronous drive) with reticle stage RST (reticle R).
After the lapse of the acceleration time Ta and the settling time Tb from the start of acceleration, the main controller 20 controls the heads 601、602、603(encoder 70)1、702、703) As a result of the measurement of (a), wafer stage WST1 is driven at a constant speed along a straight path (scanning exposure path) indicated by a solid line in fig. 10D. Accordingly, exposure area IA (exposure center P) is from irradiation area S21Moves to the + Y end at a constant speed to irradiate the region S21Is scanned and exposed.
Main control device 20 and the irradiation area S21In parallel to the scanning exposure of the irradiation region S21Part Q of the scanning exposure path of3The operation of constant velocity movement of wafer stage WST1 is performed in parallel with the above-described connection calculation. The main controller 20 irradiates the area S at 21 st21After scanning exposure, wafer stage WST1 passes through the 21 st irradiation region S at a constant speed21Switching occurrence position P of + Y side of3The secondary readhead 60 to be used1、602、603Switched to the read head 602、603、604. At this time, main controller 20 uses head 60 to be newly used after switching in the above-described sequential process in order to ensure continuity of the position measurement results of wafer stage WST1 before and after switching4Measured value C of4The coordinate offset O obtained by the successive calculation is used for resetting.
After switching, the main controller 20 responds to the head 602、603、604(encoder 70)2、703、704) The measurement result of (a) is used to drive (position control) wafer stage WST1 to the next irradiation area S22And (4) moving in steps. At this time, the exposure center P is from the irradiation region S21The + Y end of the area B draws a U-shaped track and temporarily exits the area B3Then returns to the area B0Inward toward the next irradiation region S22。
Then, the exposure center P is set in the 23 rd irradiation region S2326 th irradiation region S26From the region B by exposure treatment3To region B0After moving, proceed to area B0Inner 27 th irradiation region S27To the region B by exposure4Inner 28 th irradiation region S28When the step moves, the head is switched (12 th switching). Here, the used slave readhead 602、603、604Switched to the read head 603、604、601. The detailed operation is the same as the aforementioned 1 st switching.
Similarly, the exposure center P is in the 31 st irradiation region S3133 rd irradiation region S33From the region B by exposure treatment4To region B0After moving, proceed to area B0Inner 34 th irradiation region S34To the region B by exposure3Inner 35 th irradiation region S35When the step moves, the head is switched (13 th switching). Here, the used slave readhead 603、604、601Switched to the read head 602、603、604. The detailed operation is also the same as the aforementioned 1 st switching.
By the above-described switching procedure and the subsequent processing of the heads, the switching of the heads during the scanning exposure of each shot area on the wafer does not occur during the exposure operation by the step-and-scan method, and therefore, it is possible to maintain sufficient pattern overlay accuracy and realize stable wafer exposure processing. In addition, in the scanning exposure, since the successive calculation is performed while wafer stage WST1(WST2) is moving at a constant speed, and the successive processing and head switching are performed immediately after the scanning exposure using the result of the successive calculation, continuity of the position measurement result of the wafer stage before and after head switching can be ensured.
Next, as example 2, the wafer W shown in FIG. 13 will be described2And (4) an exposure operation. Here, in the wafer W2As shown in fig. 14 in an enlarged scale, all 38 irradiation regions S having odd numbers arranged in the X-axis direction and even numbers arranged in the Y-axis direction1～S38。
To wafer W2The step-and-scan exposure is performed along the path shown in fig. 15. In fig. 15, there is shown an area B corresponding to the head group facing the scale plate 21 when the wafer stage WST1 is located at the exposure center P in the path overlapping the path0～B4And a position where switching with the head occurs. Fig. 15 is the same as fig. 9.
First, the exposure center P is in the 1 st irradiation region S1From the region B1 to the region B by the exposure processing of (c)0After moving, proceed to area B0Inner 2 nd irradiation region S2To the region B by exposure2Inner 3 rd irradiation region S3When the step moves, the head is switched (1 st switching). Here, as described above, the exposure center P is located in the region B1、B0、B2Internal, respectively, are read heads 604、601、602All of the read heads 601～604Reading head 601、602、603Opposite the scale plate 21. Therefore, in the 1 st switching, the head to be used is taken from the head 604、601、602Switched to the read head 601、602、603. The detailed operation is similar to that of the wafer W in the above-mentioned example 11The same as in the 1 st handover.
In the same manner as the above-described 1 st switching, the exposure center P is in the 4 th irradiation region S4Irradiation region S of No. 66From the region B by exposure treatment2To region B0After moving, proceed to area B0Inner 7 th irradiation region S7To the region B by exposure1Inner 8 th irradiation region S8In the step movement, the head switching (2 nd switching) occurs. At this time, the head slave 60 is used1、602、603Switched to the read head 604、601、602。
Then, the wafer W is processed2An 11 th irradiation region S arranged in the X-axis direction at the center in the Y-axis direction (line 3)1119 th irradiation region S19In step-and-scan exposure, the exposure center P passes through the region B0In the region B1、B4Or region B2、b3And (4) moving. At this time, the head is switched (3 rd to 10 th switching). Similarly, the 20 th irradiation region S arranged in the X-axis direction in the 4 th row is formed20Irradiation region S No. 2828In step-and-scan exposure, the exposure center P passes through the region B0In the region B1、B4Or region B2、B3And (4) moving. At this time, head switching (11 th to 18 th switching) occurs. The exposure center P passes through the region B0In the region B1、B4While moving between the heads 604、601、602And a read head 603、604、601In the region B2、B3When moving, then at the reading head 601、602、603And a read head 602、603、604To switch between the reading heads in use.
FIG. 16A shows a circle C in FIG. 15 for explaining the 3 rd and 4 th switching representing the 3 rd to 18 th switching in detail3The inside is enlarged. As can be seen from FIG. 16(A), the 11 th irradiation region S11And 12 th irradiation region S12Is located in the region B0And region B1In the crossing field of (1). Track crossing region B of exposure center P0And in the region B1、B4And (4) unfolding the components. That is, the exposure center P spans the region B0In the region B1、B4And go back and forth.
In this example, the irradiation region of the exposure object is not completely included in the region B0The detailed procedures for switching between the 3 rd and 4 th modes and the wafer W1There are several differences in the detailed procedures of the 8 th and 9 th handovers. Therefore, the 3 rd and 4 th handovers will be described in detail with emphasis placed on the differences.
The main controller 20 performs the 10 th irradiation region S10After the exposure process of (2), according to the head 604、601、602(encoder 70)4、701、702) The wafer stage WST1 is driven (position controlled) so that the exposure center P is directed to the 11 th irradiation region S along the path indicated by the broken line in fig. 1511The acceleration start position of the exposure is moved stepwise.
After the step movement, main controller 20 starts wafer stage WST1 (wafer W)1) Is driven in synchronization with the acceleration of reticle stage RST (reticle R). After the acceleration time (Ta) has elapsed from the start of acceleration, the velocities of both stages WST1, RST are constant.
Further, during the exposure time (Tc) after the settling time (Tb), the main controller 20 controls the heads 604、601、602(encoder 70)4、701、702) Wafer stage WST1 is driven at the same speed as the measurement result of (a). Accordingly, the exposure center P moves at a constant speed along a straight path (scanning exposure path) indicated by a solid line in fig. 16 a. That is, exposure area IA (exposure center P) is from irradiation area S11Moves to the + Y end at a constant speed to irradiate the region S11Is scanned and exposed.
Main control device 20 and the pair of wafers W1Same as in the 8 th and 9 th switching, as in the irradiation region S11Is parallel to, strictly speaking, the irradiation region S11Part Q of the scanning exposure path of5The operation of constant velocity movement of wafer stage WST1 is performed in parallel with the above-described connection calculation. Main controlThe device 20 is in the 11 th irradiation region S11After the scanning exposure, wafer stage WST1 passes through the 11 th irradiation region S at a constant speed11Switching occurrence position P of + Y side of5The secondary readhead 60 to be used4、601、602Switched to the read head 603、604、601(3 rd handover). At this time, main controller 20 uses head 60 to be newly used after switching in the above-described sequential process in order to ensure continuity of the position measurement results of wafer stage WST1 before and after switching3Measured value C of3The coordinate offset O obtained by the successive calculation is used for resetting.
After switching, the main controller 20 responds to the head 603、604、601(encoder 70)3、704、701) The measurement result of (a) is used to drive (position control) wafer stage WST1 to direct it to the next irradiation region S12And (4) moving in steps. At this time, the exposure center P is from the irradiation region S11The + Y end of the area B draws a U-shaped track and temporarily exits the area B4Then returns to the area B0Inward toward the next irradiation region S22。
During the stepping movement, when the exposure center P reaches the acceleration start position, the irradiation region S is irradiated12Main controller 20 starts wafer stage WST1 (wafer W) in the exposure process of (1)1) Acceleration (synchronous drive) with reticle stage RST (reticle R). However, due to the irradiation region S12Is located in the region B0And region B1Thus, the 12 th irradiation region S is generated12The need to switch the read head in a scanning exposure. Therefore, the 4 th switching is performed in the 12 th irradiation region S12Before scanning exposure of (2), the head to be used is taken from the head 603、604、601Switched to the read head 604、601、602。
In the 4 th switching, the main controller 20 follows a U-shaped path from the irradiation area S to the exposure center P before switching11Toward the irradiation region S12Path of step-by-step movementFor the partial short straight line section Q passing through the stable time Tb6The above-described connection calculation is performed in parallel with the operation of driving wafer stage WST1 at the same speed. The main controller 20 performs the 12 th irradiation area S12Before scanning exposure, wafer stage WST1 passes through 12 th irradiation region S at a constant speed12Switching occurrence position P of + Y side of6The secondary readhead 60 to be used3、604、601Switched to the read head 604、601、602. At this time, main controller 20 uses head 60 to be newly used after switching in the above-described sequential process in order to ensure continuity of the position measurement results of wafer stage WST1 before and after switching2Measured value C of2The coordinate offset O obtained by the successive calculation is used for resetting.
After switching, the main controller 20 responds to the head 604、601、602(encoder 70)4、701、702) As a result of the measurement of (a), wafer stage WST1 is moved at a constant speed along a straight path (scanning exposure path) indicated by a solid line in fig. 16 a. Accordingly, exposure area IA (exposure center P) is irradiated from irradiation area S at a constant speed12Moves the + Y end to the-Y end, irradiates the area S12Is scanned and exposed.
However, the following calculation in the settling time Tb is performed by the distance (linear section Q) by which wafer stage WST1 is driven at a constant speed6Distance) is short, and a sufficiently stable coordinate offset O may not be obtained.
To prevent the occurrence of the above-described situation, as the 1 st method for sufficiently securing (obtaining a sufficiently stable coordinate offset O) the time for performing the subsequent calculation, it is conceivable that the exposure center P is directed to the irradiation region S along the U-shaped path in fig. 16 a while the wafer stage WST1 is being accelerated12A sufficiently long curve section Q passing through the middle of the step movement and the acceleration time Ta (or the deceleration overscan time Te and the acceleration time Ta)6The operation of driving wafer stage WST1 is performed in parallel with the above-described sequential calculation. However, at this time, the crystal grainsSince wafer stage WST1 is accelerated, there is a possibility that an error occurs in the measurement of the position of the stage by encoder system 70.
That is, as shown in fig. 17(a), encoder system 70 of the present embodiment includes head 60 mounted on wafer stage WST11The opposite scale plates 21 and 22 parallel to the Z axis are irradiated with measuring beams. However, when wafer stage WST1 is subjected to acceleration in the direction indicated by the arrow (-X direction) in fig. 17B, for example, encoder head 601The installation position of (3) is displaced in the + X direction with respect to wafer stage WST1 and the installation posture is inclined in the θ y direction. Thus, the measuring beam is inclined and irradiated to a point on the scale plate 21(22) deviated from the irradiation point on the design, and a measurement error occurs.
Therefore, considering that the acceleration time may be calculated continuously, the relationship between the acceleration of wafer stage WST1(WST2) and the measurement error of encoder systems 70(71) may be measured in advance, and the measurement result of encoder systems 70(71) may be corrected using the measured data during the operation of the exposure apparatus. Alternatively, measurement head 60 may be provided on wafer stage WST1(WST2)1～604The position and inclination of the head 60, and the measurement result of the measuring device1～604The measurement value of.
As the 2 nd method for sufficiently securing the time for performing the continuation operation, as shown in fig. 16(B), it is conceivable to provide a redundant section Q in the step path6"to extend the constant-speed movement section of wafer stage WST1 (i.e., section Q in FIG. 16A)6) The subsequent calculation is performed while wafer stage WST1 is driven at a constant speed in this section.
As a method 3 for sufficiently securing the time for performing the successive calculation, it is conceivable to provide the encoder head 60 with a sufficient time1～604And the condition (B ≧ bi + L +2t) for the configuration and arrangement of the scale plate 21, the condition B ≧ bi +2La +2t (i.e., the condition B ≧ bi + Max (L, 2La) +2t) is added in consideration of the Y-axis direction distance La of the U-shaped step section.
FIG. 16(C) is an enlarged view of FIG. 1Circle C in 54Inside. However, in FIG. 16C, the area B is divided into two areas according to the condition B ≧ bi + Max (L, 2La) +2t0Expanding in the Y-axis direction. In the case of FIG. 16(C), the U-shaped step interval is completely contained in the region B0Within, and therefore in the irradiated area S19After the scanning exposure, only the irradiation region S20The switching of the heads (switching of 10 th in FIG. 15) is required for the Y step, and the switching of 3 rd to 9 th and the switching of 11 th to 18 th in FIG. 15 are not required.
Moreover, condition B ≧ bi + Max (L, 2La) +2t is not limited to wafer W, for example2The same arrangement of the irradiation regions in which even irradiation regions are arranged in the Y-axis direction can be applied to any arrangement of the irradiation regions.
Then, the 29 th irradiation region S is performed at the exposure center P2931 st irradiation region S31From the region B by exposure treatment4To region B0After moving, area B is performed0Inner 32 nd irradiation region S32To the region B by exposure3Inner 33 rd irradiation region S33When the step moves, the head is switched (19 th switching). At this time, the head slave 60 is used3、604、601Switched to the read head 602、603、604. The detailed operation is the same as the aforementioned 1 st switching.
Similarly, the 36 th shot region S is performed at the exposure center P36From the region B by exposure treatment3To B0After moving, area B is performed0Inner 37 th irradiation region S37To the region B by exposure4Inner 38 th irradiation region S38When the step moves, the head is switched (20 th switching). At this time, the head slave 60 is used2、603、604Switched to the read head 603、604、601. The detailed operation is also the same as the aforementioned 1 st switching.
By the above-described switching procedure and the subsequent processing of the heads, the switching of the heads during the scanning exposure of each shot area on the wafer does not occur during the exposure operation by the step-and-scan method, and therefore, it is possible to maintain sufficient pattern overlay accuracy and realize stable wafer exposure processing. Further, main controller 20 performs a sequential operation while wafer stage WST1(WST2) is moving at a constant speed during the scanning exposure, and uses the result to perform a sequential process and head switching immediately after the scanning exposure. Alternatively, main controller 20 performs the continuing calculation while wafer stage WST1(WST2) is moving at a constant speed during the stepping movement, or performs the continuing calculation while performing the acceleration correction during the acceleration movement, and uses the result to perform the continuing processing and the head switching immediately after the scanning exposure. In this way, continuity of coordinates of the position measurement results of the wafer stage before and after switching of the head is ensured.
Next, the principle of position measurement in the 3-degree-of-freedom directions (Z, θ x, θ y) by the encoder systems 70 and 71 will be further described. Here, the encoder readhead 601～604Or encoder 701～704The measurement result or measurement value of (2) is referred to as an encoder reading head 601～604Or encoder 701～704The Z-axis direction of (a).
This embodiment, due to the use of an encoder readhead 60 as described above1～604And the scale plate 21 is configured and arranged so that the wafer stage WST1(WST2) is located in an area A within the exposure time movement area0～A4Encoder readhead 601～604At least three of which are associated with (corresponding parts 21 of) the scale plate 211～214) Are opposite. The effective measurement value is sent from a reading head (encoder) facing the scale plate 21 to the main control device 20.
Main control device 20 according to encoder 701～704The position (Z, θ x, θ y) of wafer stage WST1(WST2) is calculated from the measurement results of (a). Here, the encoder 701～704A measurement value in the Z-axis direction (a measurement direction other than the Z-axis direction, that is, a measurement value C in one axis direction in the XY plane1～C4Distinguished by being respectively recorded as D1～D4) The following expressions (5) to (8) depend on the position (Z, θ x, θ y) of wafer stage WST1(WST 2).
D1＝－ptanθy+ptanθx+Z…(5)
D2＝ptanθy+ptanθx+Z…(6)
D3＝ptanθy－ptanθx+Z…(7)
D4＝－ptanθy－ptanθx+Z…(8)
Where p is the distance from the center of the wafer table WTB1(WTB2) to the X-axis and Y-axis directions of the head (see fig. 5).
Main control apparatus 20 is controlled based on area A where wafer stage WST1(WST2) is located0～A4The position (Z, θ x, θ y) of wafer stage WST1(WST2) is calculated by selecting an equation based on the measurement values of the three heads (encoders) from equations (5) to (8) and solving a connected cubic equation composed of the three selected equations. For example, wafer stage WST1 (or WST2) is located in zone A11In the case of the inside, the head 60 of the main controller 201、602、604(encoder 70)1、702、704) (or read head 60)1、602、604(encoder 71)1、712、714) In the measurement value of (5), (6) and (8), and the measurement value is expressed by substituting the measurement value in each of the formulas (5), (6) and (8) in a cubic program.
In addition, when wafer stage WST1 (or WST2) is located in area A00In the inner case, the slave reading head 601～604(encoder 70)1～704) (or read head 60)1～604(encoder 71)1～714) Any three are selected) and a connected equation of a combination of equations based on the measured values of the selected three heads is used.
Main control device 20 performs focus leveling control of wafer stage WST1 (or WST2) within the exposure time movement area based on the calculation results (Z, θ x, θ y) and the step difference information (focus mapping data).
When wafer stage WST1 (or WST2) is located within the measurement time movement area, main control apparatus 20 measures positional information in the 3-degree-of-freedom direction (Z, θ x, θ y) using encoder system 70 or 71. Here, the measurement principle and the like are changed to (the portion 21 of) the scale plate 21 except that the exposure center is changed to the detection center of the alignment system ALG1～214) Portion 22 replaced by scale plate 221～224) Otherwise, the same is true for the case where wafer stage WST1 is located in the previous exposure time movement region. Main controller 20 performs focus leveling control of wafer stage WST1 or WST2 based on the measurement result of encoder system 70 or 71. In addition, the moving area (measuring station) may not be focused and leveled at the measuring time. That is, the mark position and the step information (focus mapping data) are acquired first, and the Z tilt of the wafer stage at the time of acquisition (measurement) of the step information is subtracted from the step information to acquire the step information with respect to the reference surface, for example, the upper surface of the wafer stage. During exposure, focusing and leveling can be performed based on the step information and the position information of the wafer stage (reference surface) in the 3-degree-of-freedom direction (Z, θ x, θ y).
Further, main controller 20 causes heads 60 to face scale plates 21 and 22 in accordance with the positions of wafer stages WST1 and WST21～604For at least one different three. Here, when the encoder heads are switched, the same following process as described above is performed to ensure continuity of the position measurement result of wafer stage WST1 (or WST 2).
As described above in detail, in exposure apparatus 100 of the present embodiment, four heads 60 mounted from wafer stages WST1 and WST2 are provided on scale board 21 covering the range of movement of wafer stages WST1 and WST2 except for the area immediately below projection optical system PL (alignment system ALG) in exposure apparatus 100 of the present embodiment1～604The measuring beams are irradiated to measure 6 degrees of freedom (X, Y, Z, thetax, thetay) of the wafer stages WST1 and WST2,θ z) direction of the position information. Furthermore, the read head 601～604The arrangement interval A, B is set to be larger than the widths ai and bi of the openings of the scale plates 21 and 22, respectively. Thus, the four heads 60 are moved from the positions of the wafer stages WST1 and WST21～604By switching the three heads facing the scale plates 21 and 22, the positional information of the wafer stages WST1 and WST2 can be obtained (measured).
In the exposure apparatus 100 of the present embodiment, the head 601～604The arrangement interval A, B is set to be larger than the sum of the opening widths ai and bi of the scale plates 21 and 22 and the width W, L of the irradiation region. In this way, while wafer stages WST1 and WST2 holding wafers are driven for scanning (at a constant speed) to expose the wafers, head 60 can be switched without switching1～604In the case of (3), positional information of wafer stages WST1 and WST2 is measured. Therefore, the pattern can be formed on the wafer with good accuracy, and particularly, the overlay accuracy can be maintained with high accuracy in the exposure of the 2 nd layer and thereafter.
In the exposure apparatus 100 of the present embodiment, four heads 60 are used1～604The wafer stages WST1 and WST2 holding the wafer are driven to be scanned (at a constant speed) by exposing the irradiation region subjected to exposure on the wafer based on the measurement results of the positional information of the wafer stages WST1 and WST2 measured, and after driving, the wafer stages WST1 and WST2 are driven from the four heads 60 depending on the positions of the wafer stages WST1 and WST21～604Wherein a read head group of the triplets (including at least one different read head) for measuring the position information is switched to another read head group. Alternatively, wafer stages WST1 and WST2 are step-driven to the start point of (constant speed) scanning drive for the irradiation region subject to exposure by using the measurement result of the positional information, and after the step-driving, four heads 60 are moved depending on the positions of wafer stages WST1 and WST2 before wafer stages WST1 and WST2 are (constant speed) scanning driven for exposing the irradiation region subject to exposure1～604The read head group (containing different read heads) used for the measurement of the position information is switched to another read head group. Thus, in order to expose the waferWhile wafer stages WST1 and WST2 holding wafers are driven for scanning (at a constant speed), head 60 can be switched without switching1～604In the case of (3), positional information of wafer stages WST1 and WST2 is measured. Therefore, the pattern can be formed on the wafer with good accuracy, and particularly, the overlay accuracy can be maintained with high accuracy in the exposure of the 2 nd layer and thereafter.
Incidentally, in the above embodiment, at least one auxiliary head may be provided near the heads at the four corners of the upper surface of the wafer stage, and when an abnormality in measurement occurs in the main head, the measurement is continued by switching to the adjacent auxiliary head. In this case, the above arrangement condition can be applied to the auxiliary head.
Incidentally, in the above-described embodiment, the portions 21 of the scale plates 21, 22 are referred to1～214、221～224The case where the two-dimensional diffraction grating RG is formed on the lower surface of each of the encoder heads 60 is exemplified, but not limited thereto1～604The above-described embodiments can also be applied to a 1-dimensional diffraction grating in which the measurement direction (the axial direction in the XY plane) is the periodic direction.
In the above embodiment, the heads 60 are each provided with a plurality of heads1～604(encoder 70)1～704) The case of using a two-dimensional encoder in which the one-axis direction and the Z-axis direction in the XY plane are the measurement directions has been exemplified, but the present invention is not limited thereto, and a 1-dimensional encoder in which the 1-axis direction in the XY plane is the measurement direction and a 1-dimensional encoder in which the Z-axis direction is the measurement direction (a surface position sensor of a non-encoder type or the like) may be used. Alternatively, a two-dimensional encoder may be used in which 2-axis directions orthogonal to each other in the XY plane are used as measurement directions. Further, a 3-dimensional encoder (3DOF sensor) having 3 directions of the X-axis, Y-axis, and Z-axis directions as measurement directions may be used.
Incidentally, although the above embodiment has been described with respect to the case where the exposure apparatus is a scanning stepper, the present invention is not limited to this, and the above embodiment can be applied to a stationary exposure apparatus such as a stepper. Even in a stepper or the like, by measuring the position of a stage on which an object to be exposed is mounted by an encoder, unlike the case of measuring the stage position by an interferometer, the occurrence of a position measurement error due to air fluctuation can be made almost zero, and the stage can be positioned with high accuracy based on the measurement value of the encoder, and as a result, a reticle pattern can be transferred onto a wafer with high accuracy. In addition, the above embodiment can be applied to a step & stick type projection exposure apparatus in which an irradiation region and an irradiation region are combined. The above-described embodiments can also be applied to a multi-stage exposure apparatus including a plurality of wafer stages, as disclosed in, for example, U.S. Pat. No. 6,590,634, U.S. Pat. No. 5,969,441, and U.S. Pat. No. 6,208,407. The above-described embodiments can also be applied to an exposure apparatus including a measurement stage including a measurement member (e.g., a reference mark and/or a sensor) that is different from the wafer stage, as disclosed in, for example, U.S. patent application publication No. 2007/0211235 and U.S. patent application publication No. 2007/0127006.
The exposure apparatus of the above embodiment may be a liquid immersion type exposure apparatus as disclosed in, for example, international publication No. 99/49504 and U.S. patent application publication No. 2005/0259234.
The projection optical system in the exposure apparatus according to the above-described embodiment is not limited to the reduction system, and may be any of an equal magnification system and an enlargement system, the projection optical system PL is not limited to the refraction system, and may be any of a reflection system and a catadioptric system, and the projection image may be any of an inverted image and an erect image.
The illumination light IL is not limited to ArF excimer laser light (wavelength 193nm), but may be ultraviolet light such as KrF excimer laser light (wavelength 248nm), or F2Vacuum ultraviolet light such as laser light (wavelength 157 nm). It is also possible to amplify a single wavelength laser light in the infrared region or the visible region emitted from a DFB semiconductor laser or a fiber laser as a vacuum ultraviolet light using an erbium-doped (or both erbium and ytterbium) fiber amplifier as disclosed in, for example, U.S. Pat. No. 7,023,610,and converting the wavelength into ultraviolet harmonic wave by nonlinear optical crystal.
In the above-described embodiments, although a light-transmissive mask (reticle) in which a predetermined light-shielding pattern (or phase pattern or light-reducing pattern) is formed on a light-transmissive substrate is used, an electronic mask (including a DMD (Digital Micro-mirror device) which is a type of non-light-emitting image display device (spatial light modulator) also called a variable-shape mask, an active mask, or an image generator) in which a transmission pattern, a reflection pattern, or a light-emitting pattern is formed from electronic data of a pattern to be exposed as disclosed in, for example, U.S. Pat. No. 6,778,257 may be used instead of the reticle. In the case of using the variable shaping mask, since the stage on which the wafer, the glass plate, or the like is mounted is scanned with respect to the variable shaping mask, the same effects as those of the above-described embodiment can be obtained by measuring the position of the stage using the encoder system and the laser interferometer system.
In addition, the above embodiments can also be applied to an exposure apparatus (lithography system) for forming a line & space (line & space) pattern on a wafer W by forming interference fringes on the wafer W as disclosed in, for example, international publication No. 2001/035168.
Further, the above-described embodiments can be applied to an exposure apparatus in which two reticle patterns are combined on a wafer through a projection optical system and one irradiation region on the wafer is double-exposed substantially simultaneously by one scanning exposure, as disclosed in, for example, U.S. Pat. No. 6,611,316.
Incidentally, the object to be patterned (exposure object to which the energy beam is irradiated) in the above-described embodiment is not limited to the wafer, and may be other objects such as a glass plate, a ceramic substrate, a film member, or a reticle master.
The exposure apparatus is not limited to exposure apparatuses for semiconductor manufacturing, and can be widely applied to, for example, exposure apparatuses for liquid crystal that transfer a liquid crystal display element pattern to a square glass plate, and exposure apparatuses for manufacturing organic EL, thin film magnetic heads, image pickup elements (CCD and the like), micromachines, DNA chips, and the like. In addition, the present invention is applicable not only to microdevices such as semiconductor devices, but also to exposure apparatuses for transferring a circuit pattern onto a glass substrate, a silicon wafer, or the like in order to manufacture a reticle or a mask used in a light exposure apparatus, an EUV exposure apparatus, an X-ray exposure apparatus, an electron beam exposure apparatus, or the like.
Incidentally, the disclosures of all publications on exposure apparatuses and the like, international publications, U.S. patent application publications, and U.S. patent specifications cited in the above description are incorporated as a part of the present specification.
Incidentally, electronic components such as semiconductors are manufactured through a step of performing function and performance design of the components, a step of manufacturing a reticle based on this design step, a step of manufacturing a wafer from a silicon material, a photolithography step of transferring a mask (reticle) pattern to a wafer in the exposure apparatus (pattern forming apparatus) and the exposure method thereof according to the above-described embodiments, a development step of developing an exposed wafer (object), an etching step of etching and removing exposed members except for portions where the resist remains, a resist removal step of removing an unnecessary resist after etching, a component assembly step (including a dicing step, a bonding step, a packaging step), an inspection step, and the like. In this case, since the exposure apparatus and the exposure method according to the above embodiments are used in the photolithography process, a device with high volume can be manufactured with good productivity.
In the exposure apparatus (patterning apparatus) according to the above embodiment, various subsystems including the respective components recited in the claims of the present application are assembled and manufactured so as to maintain predetermined mechanical, electrical, and optical accuracies. To ensure the various accuracies described above, adjustments are made to various optical systems to achieve optical accuracy, to various mechanical systems to achieve mechanical accuracy, and to various electrical systems to achieve various electrical accuracy before and after this assembly. The steps of assembling the various subsystems to the exposure apparatus include mechanical connection, electrical circuit connection, and pneumatic circuit connection among the various subsystems. Before the step of assembling the various subsystems into the exposure apparatus, there is, of course, an assembling step of the various subsystems. After the step of assembling the various subsystems into the exposure apparatus is completed, the overall adjustment is performed to ensure various accuracies of the entire exposure apparatus. In addition, the exposure apparatus is preferably manufactured in a clean room in which temperature, cleanliness, and the like are controlled.
Industrial applicability
As described above, the exposure apparatus and the exposure method of the present invention are suitable for exposing an object. Further, the device manufacturing method of the present invention is very suitable for manufacturing electronic devices such as semiconductor devices or liquid crystal display devices.

Claims (34)

1. An exposure apparatus for exposing a plurality of divisional areas of an object with illumination light through a projection optical system, respectively, the apparatus comprising:
a stage having a holder for holding the object;
a drive system that drives the stage to move the object in a 6-degree-of-freedom direction including 1 st and 2 nd directions orthogonal to each other in a predetermined plane perpendicular to an optical axis of the projection optical system;
a measurement system having four heads that are provided on the stage and that irradiate measurement beams from below onto a scale member having four portions that form reflection gratings, respectively, and that measures positional information of the stage in the 6-degree-of-freedom direction; and
a control system that controls driving of the stage by the drive system based on the position information measured by the measurement system, and switches one head used for the measurement to another head during the driving of the stage;
wherein the scale member has an opening defined by the four portions, and is disposed such that the projection optical system is located within the opening in the 1 st and 2 nd directions;
the four heads are arranged with respect to the stage such that a distance between two of the four heads in the 1 st direction is greater than a width of the opening, and a distance between two of the four heads in the 2 nd direction is greater than the width of the opening;
the moving region in which the stage moves during exposure of the object includes a 1 st region in which three heads other than the 1 st head among the four heads respectively oppose three parts other than the 1 st part among the four parts, a 2 nd region in which three heads other than the 2 nd head different from the 1 st head among the four heads respectively oppose three parts other than the 2 nd part different from the 1 st part among the four parts, a 3 rd region in which three heads other than the 3 rd heads other than the 1 st and 2 nd heads among the four heads respectively oppose three parts other than the 3 rd part different from the 1 st and 2 nd parts among the four parts, a three head other than the 4 th head different from the 1 st, 2 nd and 3 rd heads among the four heads respectively oppose three parts other than the 1 st and 2 nd parts among the four parts, A 4 th region in which three portions other than the 4 th portion of the 3 rd portion face each other, and a 5 th region in which the four heads face the four portions, respectively;
the drive system moves the stage from one of the 1 st, 2 nd, 3 rd and 4 th areas to a different area from the one of the 1 st, 2 nd, 3 rd and 4 th areas through the 5 th area during exposure of the object; and
the control system switches the one head to the other head when the stage moves from the 5 th region to the different region.
2. The exposure apparatus according to claim 1, wherein the switching is performed during movement of the stage within the 5 th area.
3. The exposure apparatus according to claim 2, wherein positional information of the stage moving within the 5 th region is measured by three heads used for the measurement in the one region.
4. The exposure apparatus according to claim 3, wherein one of the three heads used for the measurement in the 5 th region is switched to the other of the four heads different from the three heads;
and measuring the position information of the carrier moving in the different areas by the other heads and two heads except the one head among the three heads.
5. The exposure apparatus according to claim 4, wherein the position information to be measured by the other head is determined based on the position information measured with the three heads used before the switching.
6. The exposure apparatus according to claim 5, wherein the position information to be measured by the other head is determined during movement of the stage within the 5 th region.
7. The exposure apparatus according to claim 6, wherein the four heads are capable of measuring position information of the stage in both the 1 st direction or the 2 nd direction and the 3 rd direction orthogonal to the 1 st and 2 nd directions, respectively, to determine position information of the both directions to be measured by the other heads.
8. The exposure apparatus according to claim 7, wherein the four portions respectively form a reflection-type two-dimensional grating arranged substantially parallel to the predetermined plane.
9. The exposure apparatus according to any one of claims 1 to 8, wherein the control system controls driving of the stage while compensating for a measurement error of the measurement system caused by at least one of a manufacturing error of the scale member, an acceleration of the stage, and a position or an inclination of the head.
10. The exposure apparatus according to any one of claims 1 to 9, wherein the measurement system has an auxiliary head disposed close to the head, the head being switchable to the auxiliary head to continuously perform the measurement.
11. The exposure apparatus according to any one of claims 1 to 10, further comprising: a detection system, which is disposed separately from the projection optical system, and detects position information of the object; and
a scale member different from the scale member;
wherein the different scale members are arranged such that the detection is located in openings defined by four portions different from the four portions and forming reflection type gratings, respectively, in the 1 st and 2 nd directions;
during the detection of the object, the position information of the stage is measured by the measuring system.
12. The exposure apparatus according to any one of claims 1 to 11, wherein each of the plurality of divisional areas is subjected to scanning exposure;
the switching is performed during the exposure except for a scanning exposure period in which the illumination light is irradiated to the divisional area.
13. The exposure apparatus according to any one of claims 1 to 11, wherein the switching is performed outside a period of constant-speed movement of the stage.
14. The exposure apparatus according to any one of claims 1 to 13, wherein the four heads are arranged with respect to the stage such that a distance between two heads of the four heads in the 1 st direction is greater than a sum of a width of the opening and a width of the divisional region, and a distance between two heads of the four heads in the 2 nd direction is greater than a sum of the width of the opening and the width of the divisional region.
15. The exposure apparatus according to claim 14, wherein the four heads are arranged with respect to the stage such that a distance of two heads of the four heads in the 1 st direction is greater than a sum of a width of the opening and a step movement distance of the stage by 2 times.
16. The exposure apparatus according to any one of claims 1 to 15, further comprising: a mask stage for holding a mask illuminated with the illumination light; and
an encoder system that measures positional information of the mask stage;
wherein, the drive of the mask stage and the stage in the scanning exposure of the region is controlled so that the mask and the object move in the 1 st direction.
17. The exposure apparatus according to any one of claims 1 to 16, further comprising:
a stage different from the stage;
the measuring system is provided with four read heads which are arranged on the different stages and are different from the four read heads, and the position information of the different stages in the 6-degree-of-freedom direction is measured by at least three of the four different read heads.
18. An exposure method for exposing a plurality of divisional areas of an object with illumination light through a projection optical system, comprising:
driving a stage having a holder for holding the object by a driving system so that the object moves in a 6-degree-of-freedom direction including 1 st and 2 nd directions orthogonal to each other in a predetermined plane perpendicular to an optical axis of the projection optical system;
measuring positional information of the stage in the 6-degree-of-freedom direction by a measurement system having four heads that are provided on the stage and that irradiate measurement beams from below onto a scale member having four portions that respectively form reflection gratings; and
switching one head used for the measurement to another head in driving of the stage based on the position information measured with the measurement system;
wherein the scale member has an opening defined by the four portions, and is disposed such that the projection optical system is located within the opening in the 1 st and 2 nd directions;
the four heads are arranged with respect to the stage such that a distance between two of the four heads in the 1 st direction is greater than a width of the opening, and a distance between two of the four heads in the 2 nd direction is greater than the width of the opening;
the moving region in which the stage moves during exposure of the object includes a 1 st region in which three heads other than the 1 st head among the four heads respectively oppose three parts other than the 1 st part among the four parts, a 2 nd region in which three heads other than the 2 nd head different from the 1 st head among the four heads respectively oppose three parts other than the 2 nd part different from the 1 st part among the four parts, a 3 rd region in which three heads other than the 3 rd heads other than the 1 st and 2 nd heads among the four heads respectively oppose three parts other than the 3 rd part different from the 1 st and 2 nd parts among the four parts, a three head other than the 4 th head different from the 1 st, 2 nd and 3 rd heads among the four heads respectively oppose three parts other than the 1 st and 2 nd parts among the four parts, A 4 th region in which three portions other than the 4 th portion of the 3 rd portion face each other, and a 5 th region in which the four heads face the four portions, respectively;
during the exposure of the object, the stage moves from one of the 1 st, 2 nd, 3 rd and 4 th areas to a different area from the one of the 1 st, 2 nd, 3 rd and 4 th areas through the 5 th area;
when the stage moves from the 5 th area to the different area, the one head is switched to the other head.
19. The exposure method of claim 18, wherein the switching is performed during movement of the stage within the 5 th area.
20. The exposure method according to claim 19, wherein positional information of the stage moving within the 5 th region is measured by three heads used for the measurement in the one region.
21. The exposure method according to claim 20, wherein one of the three heads used for the measurement in the 5 th region is switched to the other of the four heads different from the three heads;
and measuring the position information of the carrier moving in the different areas by the other heads and two heads except the one head among the three heads.
22. The exposure method according to claim 21, wherein the position information to be measured by the other head is determined based on the position information measured with the three heads used before the switching.
23. The exposure method according to claim 22, wherein the position information to be measured by the other head is determined during movement of the stage within the 5 th region.
24. The exposure method according to claim 23, wherein the four heads measure position information of the stage in both the 1 st direction or the 2 nd direction and the 3 rd direction orthogonal to the 1 st and 2 nd directions, respectively, to determine the position information of the both directions to be measured by the other heads.
25. The exposure method according to claim 24, wherein the four portions respectively form a reflection-type two-dimensional grating arranged substantially parallel to the predetermined plane.
26. The exposure method according to any one of claims 18 to 25, wherein driving of the stage is controlled while compensating for a measurement error of the measurement system caused by at least one of a manufacturing error of the scale member, an acceleration of the stage, and a position or a tilt of the head.
27. The exposure method according to any one of claims 18 to 26, wherein the head is switched to an auxiliary head disposed in proximity to the head to continue the measurement.
28. The exposure method according to any one of claims 18 to 27, further comprising detecting position information of the object by a detection system disposed separately from the projection optical system;
wherein a scale member different from the scale member is disposed so that the detection is located in openings defined by four portions different from the four portions and forming reflection type gratings, respectively, in the 1 st and 2 nd directions;
during the detection of the object, the position information of the stage is measured by the measuring system.
29. The exposure method according to any one of claims 18 to 28, wherein each of the plurality of divisional areas is subjected to scanning exposure;
the switching is performed during the exposure operation except for a scanning exposure period in which the illumination light is applied to the divisional area.
30. The exposure method according to any one of claims 18 to 28, wherein the switching is performed outside a period of constant-speed movement of the stage.
31. The exposure method according to any one of claims 18 to 30, wherein the four heads are arranged with respect to the stage such that a distance between two heads of the four heads in the 1 st direction is greater than a sum of the width of the opening and the width of the divisional region, and a distance between two heads of the four heads in the 2 nd direction is greater than a sum of the width of the opening and the width of the divisional region.
32. The exposure method of claim 31, wherein the four heads are arranged with respect to the stage such that a distance of two heads of the four heads in the 1 st direction is greater than a sum of a width of the opening and a step movement distance of the stage by 2 times.
33. The exposure method according to any one of claims 18 to 32, further comprising measuring, by an encoder system, position information of a reticle stage that holds a reticle illuminated with the illumination light;
wherein, the drive of the mask stage and the stage in the scanning exposure of the region is controlled so that the mask and the object move in the 1 st direction.
34. The exposure method according to any one of claims 18 to 33, further comprising: holding the object with a stage different from the stage;
the position information of the different stages in the 6-degree-of-freedom direction is measured by at least three of four heads that are provided on the different stages and are different from the four heads.
A component manufacturing method, comprising:
exposing an object using the exposure apparatus according to any one of claims 1 to 17; and
the exposed object is developed.
A component manufacturing method, comprising:
exposing an object using the exposure method according to any one of claims 18 to 34; and
developing the exposed object.
HK15105600.4A 2009-08-25 2015-06-12 Exposure apparatus, exposure method, and device manufacturing method HK1205280B (en)

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US23670109P 2009-08-25 2009-08-25
US61/236,701 2009-08-25
US12/859,983 US8493547B2 (en) 2009-08-25 2010-08-20 Exposure apparatus, exposure method, and device manufacturing method
US12/859,983 2010-08-20

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HK1205280A1 true HK1205280A1 (en) 2015-12-11
HK1205280B HK1205280B (en) 2018-03-02

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